Births from 1916 - I ask for a search for George Parry - exact matches only - no mothers maiden name given
I would suggest not putting exact matches 
Really? I've always found that not using the exact matches on Ancestry causes you to get a huge number of irrelevant 'hits' -- as bad in this regard as the old IGI site.
I haven't particularly noticed the problem the OP mentions, and I've been doing a lot of searches in the post-1916 BMDs recently. I wonder, therefore, whether this is yet another reason not to use the 'new search'. I always use the old search, mainly because it's much better at searching for places -- if I put, say, Kinver in the birthplace box on its own, I get no matches on the new search, because it insists on having the full designation: Kinver, Staffordshire, England. The choice of Kinver is significant (other than being my birthplace) because it's in Staffordshire but within an hour's walk of Worcestershire and (post-1974) the West Midlands, and not much further from Shropshire. It therefore is a common candidate for misenumeration. I want to search for Kinver alone because there's only one place in the UK with that name, but it gets enumerated in several counties. Why Ancestry feels that such a facility is no longer worth providing, beats me.
Unfortunately, Ancestry periodically defaults the pages I've saved as Favorites to the new search, and it's getting increasingly difficult to get back to the old search (the number of pages which have the little 'Old search' link at top right is reducing).
On BMDs I always use FreeBMD out of preference, but obviously when you get outside FreeBMD's current coverage you haven't got much choice.