I understand that mucking in other people's code can be a pain, but if you are going to have to muck, you might as well do some "mucking out". Toss out code that is clearly problematic.
Just for example, suppose somebody *else* comes along after you and adds *another* <form> into that page. So that now the BMI form is actually forms !! That person will have to struggle with finding that wrongly numbered <form> all over again! Whereas if you use LogicAli's answer (or even my answer!) the code is now fixed so that this confusion won't have to occur again.
I hope you won't take this wrong, but if you were on my team and just changed the  to  you would be stomped all over in a code review!! (And not just by me! Every team member would call you out.)
I dont take it the wrong way and I appreciate it actually will be updated with the compute(f) I understand the right way to do things, I was just not in the mood after a day of debugging but it should be done and there is no excuses.
Again thank you.