I believe it was as is stated. Why would anyone lie about it? There were some people stating that Tuesday would have been an odd choice for a pageant as they usually do them on the weekends or on Fridays, but I do not think that it is some kind of a rule. It might have been strange, but it still could have happened. And if it were on the 15th, witch would have been Sunday, it would not have been doctors "after hours" because the doctor probably would have had his day off on Sunday. Anyway, I do not see why and how would it matter if it was on the 15th or on the 17th, as we know that the pageant happened.
The calls to the doctor could be strange, but also could just be calls. I see Patsy calling multiple times if she did not get on the line the first time. If the line was busy and she hoped he'll pick up the phone next time she called. I have called to my family doctor like that maybe even 9 times in a row without anything urgent having had to happen, but just to get it done because I might forget to call later in the day. IMO
The only thing what makes it all suspicious to me is the fact that Patsy does not recall making those calls later. Why hide? Why lie? Why not say "yeah I called a few times cause I wanted to schedule another appointment for Burke/JB before the holidays and our trip." or something along those lines. If she just would have said something like that, everyone would have been satisfied with her answer and it all would have been long forgotten. Sometimes I think that all this forgetting, lying and changing their stories, serves its own purpose.