Actually in RSC you start with 10 hp but the combat formula is different... for level 11 hp you need 1,154 exp in hitpoints and in RS2 it is 1,358 exp. so therefore...since you can be below 1154 exp because you start with about 1017 in RSC. Here are some pictures to clear it up: for lvl 11 hp in rs2... and for lvl 11 hp in RSC...