Finding Bills to reprint

I get a 27 page history report for a client and I have some bills to reprint right in the middle of a client that are totally missing.  I have just added the 2017 upgrade the last 2 months of bills are showing up and a couple from the past but all the rest of random bills are missing.  The ones that are showing is less than 10 which is the number of bills I have set for display,