The T/O performance isn't calculated based on your actual c/g, it's calculated using a "worst case scenario" for c/g which is the forwardmost one. This usually gives conservative figures for mtow, v1 etc, as you are rarely operating with c/g this much forward. If you move the forward
limit for c/g
aft, ie make sure that you will never have an actual c/g that is forward of this new limit, the manufacturer can publish better performance figures (higher rtow) simply because the "worst case scenario" in terms of c/g is improved.
Hope it makes sense...
