My accountant is very understanding about this situation and he says he has no problem with it. I've never had to file late. Last year I passed him on 01APR and I picked up the next day. I think he uses turbo tax! I'm tempted to do it myself one of these years. I've a total of 5 MLPs and EPD is always the last one to issue the K-1. I've shied away from the few that often go beyond the 15 April deadline. I suppose if the dividend was high and the risk low, I'd be tempted!
I usually do the rest of my return, exit and save and come back to TT when i get the K-1, takes 5 minutes to log on and add the info and then I send. So end of March last year. As an added bonus you get to know EXACTLY how the EPD position affects my taxes. Not once in 5 years has it added to my tax liability and occasionally adds to my return.
I'm sure your accountant doesn't use Turbotax.
The whole interview format of TT is fine for us retail investors who are only preparing one return but is way too slow and cumbersome for professionals. They have professional software which costs thousands of dollars.