I've often said the two things you should never get into diiscussions on the net about are nutrition and behavior. Perhaps I should add vaccinations.
People get very adamant that they hold the one truth about stuff where there are many 'right' ways.
Things we know, (or think we know)-
1) Like most vaccines, (Lyme, feline distemper, Feleuk, etc),you need two vaccinations about a month apart to create sufficient antibody levels. Think of it that the first causes the factories to be built, the second stimulates them to produce.
2) The problem with canine distemper is puppies get protection from the mother, which varies from nothing to up to 13 weeks. This protection also 'protects' against the vaccine working. So if you see a 6-8 week old puppy, a vulnerable age,you can't give two vaccinations a month apart and have the second after 13 weeks. You need a temporary until they are old enough to get the standard series. (Someone mentioned influenza - actully it ws measles vaccine which was used as the temporary.)
3) For parvo in particular, some individuals , especially rotties and dobes, do not develop sufficient antibody unless vaccinated later, perhaps at 16 weeks.
4) The less vaccinations the better, as long as they are sufficient to do the job. That last part is important.
Those are basically the rules, and different protocols can come out of that. One problem , for example, is that large pet stores, rather than vaccinating each individual at the ideal tiume, simply go through and vaccinate everyone every two weeks. Hence a puppy might have had vaccinations at 6,8,10, and 12 weeks, yet STILL, at least in theory, should receive another.
So as long as your veterinarian's protocols make sense in relation to these axioms, 'don't sweat the small stuff.' If they do not seem to make sense then by all means ask.
Incidentally - Dr. Shelli is welcome to correct me on any and all of this. She is the academic with more exposure to the latest info, and, like us all, I'm always learning.
