Atheros AR5213 max tx power ?

In 2.8 manual page 141 it says default tx-power is max power, but in next paragraph it says some cards’s default is NOT max.

What should I set Atheros AR5213 card’s tx-power to be sure it’s maximum, running on
1)5GHz (g)
2)2.4GHz (b/g)


Thanks

default. it will work the best that way. use tx-power setting only to lower the power