Hi,
I specialize in creating custom-made, interactive PDF forms, including all the required scripts to make them work as they should. I have a lot of experience with forms similar to the one you described (including various time-based validations) and I can do it for you quickly and professionally. However, the file you shared was created in LiveCycle Designer, which is a problem. I suggest to convert it to a standard PDF form for you as well as adding the scripts, hence my somewhat high quote...
Regards, Gilad (try67)