Should I take Science as a sixth skill?

I'm doing a Very hard run. I am running with the easily distracted perk leveling locking, hack, medical, engineering, and speech. At the end they will all be at 18. My question is if I should add science for extra TTD and elemental effects. Doing so would mean that all skills end at 15 instead of 18. I didn't pay as much attention during my first playthrough, how many times will having a 15 instead of an 18 matter for skill checks? Are they important? Any advice would be appreciated.