You will not extend the flaps above FL200, ( you can fly with flap already extended) if situation requires. Therefore clean, above FL200 the amber band is a reflection of buffet and is limited by thrust, OAT and Weight. In LNAV real time bank angle protection will limit the roll, if you use HDG select you may over bank. In short, 1.3 G is not guaranteed and ref to this is found in the LRC MAX operating altitude tables.