The corpse is undamaged and I have level 5 survival. All the yields are ~40% lower than the mass ratios
If I repeat this at survival 7, all the yields are roughly 20% lower.
I understand that the survival skill should help with butchery, but are such large differences intended? Looking into code, there is
return 0.5 * skill_level / 10 + 0.3 * ( factor + 50 ) / 100 + 0.2 * p->dex_cur / 20;
Does this mean that one can obtain more than the designated mass if your survival/dex are high enough? Survival 13 would already make this >1 for me.
Anyway, there is also the problem that field dressing/skinning reduces corpse weight and thus also the rest of the yields.