I think be careful about assumptions regarding how to make your average drop.
It is based on the LOWEST 10 of your "most recent 14" scores - and the very most recent scores are somehow "weighted" as well to give them greater emphasis. WGT does not disclose exactly how this works. (NOTE: I am fine with that).
Here is what CAN HAPPEN (numbers are hypothetical as an EXAMPLE):
Let's pretend your most recent 14 scores are as follows - with MOST RECENT listed first and oldest listed LAST:
70 74 68 67 71 68 65 70 75 68 73 69 72 64
FROM THIS GROUP, you would DROP the 74 75 73 and 72
Your average would be composed of the other 10 = 68.00 (I am not considering the "weighting" of most recents).
NOW - let's pretend you shoot a -5 round of 67 (on Kiawah).
NOW your most recent 14 will look as follows:
67 70 74 68 67 71 68 65 70 75 68 73 69 72
**NOTE THAT THE 64 you shot probably a week ago has now DROPPED OUT of your "most recent 14". It no longer counts.
Your average actually goes UP to 68.30 because where the 64 USED TO COUNT, it no longer counts and your NEW -5 score of 67 is counting instead.
Just understand that "older" really great scores will drop OUT OF your average and sometimes create this unexpected result even after you have just shot another really great score.
Something similar to this is probably what has happened in your case.
One more observation: This works THE OTHER WAY occasionally (to the player's ADVANTAGE) as well. AS FOLLOWS:
EXAMPLE: My current Average is a 66. I shoot a 66. Not great not bad BUT right in line with my average. On its surface YOU WOULD THINK there is no effect to the average. BUT SOMETIMES the most recent '66' would cause an older HIGHER score to drop from the average - and as such following a "typical" round that would appear to have no effect, the Average may actually DROP slightly. I have seen this happen in my own game from time to time.
Best Regards, AtlantaCoaster