Possibly bug in bullet M2 XW image: power level

The bullet M2 models are capable of providing up to 28 dB of power output.

When working with the bullet M2 XM models the image:

- aredn-3.20.3.1-ath79-ubnt_bullet-m-factory.bin

supports the full 28 dB of power output.

With the bullet M2 XW models the image:

- aredn-3.20.3.1-ath79-ubnt_bullet-m-xw-factory.bin

only supports 25 dB.

This appears to be a possible bug which reduces the power fomr the bullet M2 XW systems by perhaps 1/2.

Anyway to debug what is going on here?

Thanks!