For me it's about the mechanics I was taught. I haven't been evaluated in the last few years, but "Plate Cleaning" is on the eval form and my recollection is the association doesn't want you to call time.
I also agree that "they" tell you to always keep your "chest to ball" when the ball is live; however, it seems this one case it's OK not to because "they" said so. Once you've done it one way for enough time, it's hard to change.
For me It has nothing to do with the time it takes to put my hands up prior to cleaning or needing (remembering) to put the ball back in play after. It's just a mechanic. Really unless you're cleaning a large pile of dirt off the plate after a play at the plate, then it should take no more than a few seconds to quickly swiff the plate. If it's extra dirty a shoe works well before you bend down. It's not rocket science and like I said before, I'm not eating off it nor am I type "A" enough to have no spec of dirt left. Perhaps if I had OCD I'd need to swiff 3 times like Sheldon knocks 3 times on Penny's door ;-) Many plates in our area are to say the least not in the best of shape and no amount of swiffing will clean them.
On a totally unrelated issue, but yet noted in a recent response... If the catcher went to the mound without requesting time, I wouldn't call time for him. I might ask him while he's on his way if he's forgetting anything (so only he and I can hear it). But why should I "assist" the defense in making a "time" call that could benefit the offense? Catchers know to call time... They know if they don't hear time, then they need to ask again... If they don't, well it's not my job to train them. Last time they do it I bet too! Not that you want to throw the guy protecting you under the base, but if a defensive coach asks I'd have to say because he didn't call time...