Litebulbs:
2:10:05 FL350 "sharp fall from 275 kt" 275 at FL350 @ 465TAS
FL375 "speed increased sharply to 215 kt" 215 at FL375 @ 375TAS
2:11:06 ? "15 seconds later" isis 185 kt FL380 @325TAS
Not sure of the significance of TAS but these are my rough calculations.