Don't use imitation practice tests to keep score; just use them to work on concepts and test taking skills. There is absolutely NO WAY that any company can properly norm the exam. If you want to know how you'd score, buy The Official ACT book and take those exams.
Print and official exam from ACT.org site. Score it. That's your starting point.
Study from any ACT prep book, which covers all of the topics and provides strategies. Spark Notes online is free and does just fine.
Buy the Red Book--that's the official one from ACT. Take test #1 and see where you're at. Don't worry about score improvement--at first. Study every question and concept you missed. For every question you missed, ask yourself how the test writer could change the question...e.g. solve for x instead of y. This will help you find the details of the questions that most students miss.
Take test #2 after more studying. If your score is similar to your baseline, don't take another test from the ACT.
Study for at least a week with a prep book such as Barrons or PR
Now, take another test.