The MTOW is your Structural max take off weight(real weight).
The RTOW (Regulated) is your Performance adjusted take off weight which must be below your runway/obstacle level off/climb limit weight.
The adjustments are qnh,bleeds OFf,EAI ON.....
On a long runway you could see that your RTOW limit is well above your MTOW,up to 82T for a 738.