Hmmmm... when I worked in an office, I would say that every different doc/health care provider did "make up" vaccines slightly differently! And a lot depends on why the kid was going slow in the first place. As far as I know, there isn't a set anything.
You can get the most current vaccine schedule at the aap website, but be warned, then you have to see exactly which vaccines your office is stocking.
Don't stress - any nurse not used to working at that particular facility would need clarification. Ask them if they go by the APP guidelines all the time (and all the providers.)
Then if a kid is behind, ask the MD/NP/PA exactly what they are ordering that day. Then confirm with the family before giving to make sure that's what they thought too!
Don't let everyone else's pace throw you - slow down for that part and make sure you have your answer. You are in the right - making sure you give excellent care to the kiddo!
That's my take anyway!
Oh and I totally agree with you about not being able to see the chart - that would just about kill me. In NC, there's now a statewide vaccine record, but it's new and hardly utilized. If you can't see the chart and you feel reasonable sure that you're giving the right meds, I guess you can console yourself with the fact that a double dose is not harmful (at least in DTAP, hep, flu - I've called about all those before...) MMR? Poison Control and NIH say not harmful.
(A little tongue in cheek - a med error is a med error is a med error.)