I'd call 10dB in power and 20dB in E-field poor shielding and 0.4 dB loss on reflection very good for an antenna. You could take another example, 50%/50%. That's 3 dB each way. We could argue ad infinitum, but In the end, it's whatever works in a given situation. Personally, I would not make the assertion you did, and that was my point. Other's can read this exchange and understand there's a difference of opinion and come to their own conclusion.
Lou W7HV