Help for modding TDP, TDC, Max Power Limit

[Old_Timer]

I have the following issue.
My Sapphire Nitro + GPUS mine at steady 28 m/hs, while my Asus Trix 470 varies between 20 and 26 m/hs
I checked their powertune settings in bios and saw huge differences.
Sapphire
Max P. Limit : 130
TDP: 85
TDC: 115
ASUS
Max P. Limit: 95
TDP:85
TDC: 83
Do you think there could be a throttling issue?
Is it safe to change the ASUS figures to the Sapphire ones since I Do undervolt the cards?