It's my belief that excessive webforms can delay processing, because (I understand) they have a 'must be handled' rule - responded to or looked at in case it affects the file in some way. And of course, if you have a pile of them and it means the officer has to spend a lot of time going through them - yep, they're going to reach for the easy file when they have limited time / a deadline/numbers to meet etc.
But I don't think this is the case for calls, where I think they only make/record important notes.
I'm reading between the lines on this however but I don't see any reason to thnk that calls cause problems.
That said: excessive calling does add to the load on the system, keeps others from getting through, etc. But I'm not dictating how much excessive is.