All party skills can be effectively higher than 10 (Looting, Tracking, Tactics, Path-finding, Spotting, Surgery, First Aid, Engineer and Trading).
Read the skill descriptions, a 10(+4) Surgery skill gives 4%x14+25% = 81% of survival. Looting will give you a 140% increase to your share but that does not mean youget 140% of the loot.