If the well regarded roofer thought that 30 rows should be replaced then either he was trying to pad the price or the subcontractor is wrong and you may end up with problems sooner rather than later with those non- replaced shingles.
So when the time comes to replace your old roof are you going to go with this “well regarded” roofer or someone else?
The contractor has gone silent because he sensed your hostile tone. The less he says, the better if you drag him to a small claims court. Smart of him.
@MichiganGeorgia No, I am not going with this roofer. Funny you mentioned that since this was a kind of trial run to see if I could use him when I need a major roof job which will be not too far in the future.
BB, he won’t be silent forever since he has to get paid.
A contractor lien?
I doubt it. I’d think he’d rather get paid than put a lien on. Would he put a lien on and lose 40% because he wants to get paid 67%? I’ll cross that bridge when or if it comes.
I doubt this will come to the point of a mechanic’s lien being filed. @iglooo seems to be taking a reasonable approach and the roofer has every incentive to work out a solution rather than getting dragged into small claims court for what would be (IMO) an uphill battle.
It depends on how mechanic’s liens are created in your state. Here, a statute says that if a contractor does work on your house, that automatically creates a lien. There is more to that, but that is the first step. I am not a lawyer, just own real property. 
Just trying to give the OP some heads up.
The roofer didn’t fulfill the original contract, which specifies 30 rows of shingles. I would imagine, if push comes to shove, the roofer can be made to fulfill the contract. He would lose money in this case, I would guess.
I’m not a lawyer either but I’ve owned a general contracting company as well as a development company that built over 100 homes and, as such, I’m fairly conversant with a lien law.
Mechanic’s lien procedures vary by state but the general premise is that a contractor is entitled to be paid for work performed in good faith. Performing the work creates a right to file a lien, but the actual lien would need to be perfected by notifying the property owner and also filing a notice with the keeper of public records. In addition to protecting workers, state lien laws provide protections for property owners as well and, in my opinion, fear of a lien should not deter a property owner from standing up for their rights.
The language of the contract is critical, as it will address the scope of work, the payment terms, the remedies of the parties in the event of a breach, and other legal details. One important thing to keep in mind with this or any other contract is that any ambiguous language will be interpreted against the party that prepared the agreement which, in this case is presumably the roofer.
I’m not a lawyer either, but I propose this scenario:
these 2 end up in court, and the OP says- he didn’t abide by our contract it specifically said 30 rows of shingles.
The contractor will say he replaced all necessary to solve the problem and freely offered a reduced rate due to less time and less material.
The Op will then get to rebut, and will say- but the exact letter of the contract must be followed! I wanted 30 rows and only got 7!
Then the judge will say- if you believe so strongly that the contract must be followed, then why are you arguing for an even greater reduction in price than already offered, instead of trying to make him abide by the contract? If following the exact letter of the contract is so important in this case, then why isn’t the Op trying to get 23 more rows done?
That scenario demonstrates the inconsistency of those here that say the exact contract must be followed, yet do not try to force the remainder of the contract to be filled. Arguing for a greater reduction is inconsistent with arguing the exact contract must be followed, because the willingness to accept the completed work but to pay less demonstrates that doing all 30 rows isn’t as important.
It is not unlike tenants in eviction court that want to argue they shouldn’t have to pay rent because the home is uninhabitable. Yet, the reason they are in court is because they won’t vacate the home they claim is “uninhabitable”.
There’s no way on earth a building official is going to inject his/her opinion on the whether a contractor’s price is “fair”.
If the OP took that position, then, you’re right, they’d lose. But the OP isn’t a fool. More likely @iglooo would reply that the roofer misdiagnosed the extent of the job, failed to supervise the work, delegated the job to a subcontractor without the customer’s approval, and that the estimated scope of work was significantly more than what was needed, what was bid, and what was actually performed. These facts are indisputable, and were in fact conceded by the roofer when he unilaterally offered to reduce the bill.
Given the undisputed facts, the only task left for the judge would be to assign a value to the work performed. As I wrote in post #46, it is unlikely that this will result in a lien being filed, much less making to a judge’s review. Reasonable people resolve these types of disputes, @iglooo seems reasonable, and I expect the roofer isn’t an idiot.
I think you have a good point there, sherpa and may very well be right about the judge’s decision, based on the scenario presented.
But I used that scenario NOT just to present 1 possible legal scenario, but largely to point out the inconsistency of some here that have taken the tack that the contractor breached his contract calling for 30 rows of shingles. I wanted to demonstrate how the remedy for not replacing enough shingles should be replacing the unchanged portion of shingles; that is, if exactly 30 rows is so important.
@sherpa - I have lived in small towns most of my life, and have known several building inspectors. My suggestion to consult the building inspector was for an opinion as to whether the job was performed satisfactorily or not. OP cannot climb up personally to review the job, so there might be concern as to whether the fact that 7 rows were replaced instead of the initial 30 rows, was sufficient.
The initial estimate indicated 30 rows were needed, but the subcontractor, once work began, determined only 7 was okay. Getting an independent opinion from the building inspector might be available at no cost to the homeowner, or it might cost only a nominal amount - the rules vary by town/state.
In a small town environment, the building inspector can give some reassurance to the home owner that things are okay, or if he might recommend OP demanding they come back for the additional 23 rows. The way things work, the OP can ask for and “unofficially” get some guidance as to whether the job was fair or not in a conversation with the inspector - who works with contractors all day and won’t officially say anything giving preference to any particular contractor. But tone, body language, etc by the inspector as he simply repeats the options that OP has, can easily convey reassurance, or concern, as OP decides if they are on the right course.
I till think OP is going about this the right way, and hope that the contractor gets back with the breakdown requested in due course.