Extra Summon Bonus Proof

I wouldn't say lost. I would say included in the set bonus.

Except you lose 5 luck. It's not included in the set bonus, so obviously the individual bonuses are lost.

The luck is included in my set bonus......

It's not in mine, check again.

I summon an incubus - my luck goes up to 69.

I summon a succubus after summoning my incubus, my luck drops to 64.

Obviously it's lost and you haven't tested well enough.

Yes, because I'm not capable of adding 10 luck and then 5 more.

Apparently you're not, so just for you, here you go:

Base:

http://i.imgur.com/piCN9Rs.jpg?1

Incubus alone:

http://i.imgur.com/93vMDF2.jpg?1

Incubus + Succubus:

http://i.imgur.com/hO6CbIA.jpg?1

You clearly lose the original incubus bonus, and only gain +5 from the incubus + succubus set bonus.