Nah… It’s just that “usually calculations overestimate the experimental values”.

• Hey boss, we have sincere troubles, SNR is off by too much.
• how much?
• 20dB
• ah, then we’re good, that’s so ridiculous it’s def. a gain problem in your measurement setup

The funny thing about RF work is how casually a few orders of magnitudes gets thrown around. 10 dB fudge factors for assorted losses are quite common.