This is going to look complex but it is the only way i can see to explain what is going on for you.
Lets take your average and say you have have the 500 rounds for saturation, which i am confident you do with over 2k RR.
500 x 62.19(your average) = 31095 strokes in total over the 500 RR
Lets say for arguments sake that you shoot a 31 and that 31 is replacing a 33, dropping your total strokes by 2 strokes
31095 - 2 = 31093
NOw you divide the 31093 by the 500 again to get your new average
31093/500 = 62.186
WGT doesn't show a 3rd decimal and with basic rounding up and down rules your average would look like it did not move on your profile, because of the 6 they would round up keeping the shown average of 62.19
Now you shoo that 32 and it replaces a 33 also from your saturation dropping total strokes by 1 down to 31092
31092/500 = 62.184, now they would round down showing your average moving to 62.18
then you shoot another 31 replacing a 33 another 2 strokes down to 31090
31090/500 = 62.18 again not showing a move
Alot of this is hypothetical and a lot depends on what scores are being replaced by the 31 and 32 but in premise you could see how it might happen