I’m not sure I agree that the formula is “opaque”. You may not agree with the formula, but it doesn’t make it opaque. The fact that a year out, you already know that certain schools are unaffordable, based on the way your assets are allocated, clearly means it’s not opaque- it’s quite transparent. Holding retirement assets in a vehicle which is NOT a retirement account doesn’t work for some colleges. A merit aid college won’t care where your retirement assets are- or if you even have any. The aid will be based on your son’s stats, plain and simple.
Nobody is expecting you to lose your home. If you cannot afford what the NPC’s are telling you, your son needs a different list of colleges where your assets won’t be a factor.