The previous limit LED indicator on the UM200B was wrong (misleading) and led to many users setting the transmitter gain wrong (too low). After 5 years of confused users calling the sales crew, the service troops and yours truly, I decided to change The Damned Thing. The reason I think it was the right thing to do, is that the number of calls about level problems has declined dramatically.
I didn't do the change casually for the very reason some users have brought up; mixing B's and C's is confusing. If you set the LED's the same, the modulation of the UM200C will be about 10 dB (!) hotter than the B.
We told users in the UM200B manual to set the limit LED so it was on 10% of the time. The users didn't want to do that since the red LED was worrying them so they were setting it for no limit LED or occasional flashing. The new recommendation on the UM200C is for occasional flashing which is the way most users wanted to set it.
Here's what can be done:
Just use the receiver monitoring. The receiver metering has not changed and the basic audio in the transmitter didn't change either, just the transmitter readout. If you use the metering on the receivers, then the B or C transmitters will be set the same. Also, just remember to set the B's for more LED flashing than the C's.