I have used this system in two of my jets and have been extremely pleased with each. From your data I would say that everything other then flight #3 is acceptable, but I would move the "R" antenna to another location to see if you get better results. I am guessing that the "R" may be the one in your vertical fin, and the lengthy lead may cause the lower numbers.....but this is just a guess. Your system seems to be operating perfectly, don't dwell too much on flight #3.....I have had the same type of readings on one flight, then perfect the rest. Either way, the system works above my expectations and I will not fly another model without it.
Good luck,
Dave