Is there any known limit for how many dice RPG players are comfortable adding up?

After reading a few RPG systems that use successes and others that use dice whose shown number are totalled, I came to the conclusion that personally I prefer adding up a maximum of 3–4 numbers and don’t like having to add up more than that — while with counting successes I had no such preference on a limit.

Now what I’m wondering is, if there are any known studies from the gaming industry (or if there is any known census there) that shows a practical limit at which the average player says “ok that is too many dice to add up” and thus loses interest?

(To clarify, adding up 3d6 in this context means adding up the face values to get somewhere between 3–18 as a sum.)