My FICO8 recently went from 792 to 795.
The key changes: a card w/ 15% util fell to no util; 2% aggregate util fell to 1%; 4/17 cards reporting fell to 3 cards reporting (with balances on the remaining 3 ranging from not quite zero to 13%).
Would I be right in thinking that it's the single card change that impacted the score, or might the aggregate balance have mattered?
Your oldest card aging another year? 
Might be both the aggregate and/or individual drop in %'s. 5 points is hard to nail down. Could have been a sunny day for all we know. 
@Curious_George2 wrote:As between the two Util metrics, yes, individual is the likelier source of the gain than aggregate. I don't think we have seen much evidence of a scoring threshold at 2% Agg Util.
But even Ind Util isn't super likely, since you still have a card at 13%. So all that changed from a Max Ind Util perspective is that you went from 15% to 13%.
Which bureau is this? What scorecard are you on? What were your Accounts With Balance numbers, before and after (including all closed and open accounts in the denominator)? Did any aging things change, either from starting a new month or having accounts added to or removed from your file? Are you able to see any clues in reason codes?
ETA: based on your sig, it looks like your scorecard is Clean, Thick, Mature, With new Revolver. Do you agree?
Which bureau is this?
EX FICO8
What scorecard are you on?
As you described - clean, thick mature, with a couple of new cards (3/5 months) and a refi (5 mo).
What were your Accounts With Balance numbers, before and after (including all closed and open accounts in the denominator)?
3/17; 4/17 now.
Did any aging things change, either from starting a new month or having accounts added to or removed from your file?
Don't think so -- if anything, things tend to be falling off of late. reducing AAoA.
Are you able to see any clues in reason codes?
Negative.
Additional data point -- the other BT reported, with no score change. Formerly, 4K on one card (27.7K CL) now 2K and 1.8K on 2 cards (40K and 13.5K CL, respectively).
Next month and the month after, the newbies will hit 6 months.