My CS757-200 V4.3 aircraft.cfg lists the gross max weight as 221,000 lbs. and indeed that is the max that is allowed in the FSX load planning page.  In the manuals etc. I have seen up to 255,000 lbs and I have a feeling that 221,000 is too light as at this weight the FMC is calling for a initial cruising altitude of 35,000' with 37,000' 500 nm later.  This just can't be right.  What is it supposed to be and can I just change the aircraft.cfg number to a higher perhaps more correct value or will that throw off the entire performance.

Also, the OEW if 115,000 lbs seems lighter than most numbers that I have seen that are closer to 136,000 lbs.

In the manual is that statement that the max weight can range anywhere from 220,000 to 255,000 lbs.  No other expalnation is given.

Another important spec is the max zero fuel weight that this model uses.  I haven't been able to find this in the manuals.  It is an important number as this limits the amount of cargo and passengers that can be carried independent of the fuel.  This number is also critical so that you don't land with too high of a landing weight.  By the way, that is another critical number that I can't seem to find, the max landing weight.  Maybe it is in the manual and I just missed it.

Can anyone help with this? :-/