Assuming a LvL 50 SM with 50 in summoning, is using items which adds + 11 in Summoning , what is this good for ?

I remember very vague this was already discussed "ages" ago, if this would may increase dmg shild or buffs , but I cant remember if this was ever clarified.

Any help is welcome.

Tom

It helps raising a bit the cap on pet healing spell, and should increase the value of the buffs, which will just increase the absorb value of the pet (since pets are treated like mobs, and they don't have real stats). Oh yes, in case of the strcon buff, it increases the damage the pet does at melee by 1 or 2 points.
Focus shield has a fixed dps value, will not increase with +spec or +items

Short version: don't bother with +summoning items