As far as changing HC's from one test to the next, I can tell you, if I hit the " print " button on my analyzer 10 times, I will probably get 10 different numbers.
You have to remember, these numbers are in parts per million, not %. So, you can understand how small of an amount 20 or 30 ppm is.
When you get up into the hundreds or thousands of ppm on HC, that's when you start looking for some major problems.
Can't help you with this vacuum hose / throttlebody issue, sorry.