Unless you can attribute any of those 1,075 impressions and 388 engagements with a single new booking, that's far from phenominal (sic) performance.
An impression on the FB-created video ad is probably counted from the moment that it's shown, whereas your uploaded content probably requires 20-seconds or so of viewing to be counted as an impression. There are some other possibilities, too, including that the FB-created video autoplays and your uploaded content does not.
Funny you should mention that. Just got a lead for 12-11, yes, next weekend. It came in on the new website (carolynryanphotography.com), which tells me it came from FB. Not sure if I'll get the job or not but it's less than 72 hours since I started this new campaign. I call that a pretty good sign. As for the videos, I suspect you're correct about the auto-play on the FB slideshow as making the difference. I'm going to just have to keep testing the waters to know for sure what's happening.