Screenshot 7 seems to suggest that this is correct, even though it is contrary to what I posted above from screenshot 3. Screenshot 7 has a "Years of MLB Service" and "Years on 40 man Roster" with a different # of days. It looks like it's just worded poorly in screenshot 3, that 172 days constitutes a year in terms of MLB service or on the 40 man roster. I don't believe "service year" is a 40 man term. It might be good to clear this up so others don't wonder the same.
http://www.mirror1.ootpdevelopments....ns/screen7.jpg
EDIT: Or maybe it is (also a 40 man term), I don't know for sure. Nonetheless, it's usually good to eliminate any possible confusion.