I craft, a lot, on six different characters. Since the bank slot bug (loss of extra 30 slots due to bug in game) I have had to use my characters as mules. When I finish a playing run, this means logging in and out a bunch of times to stow stuff on appropriate crafter.
Fix the bank slot problem, and you will find a percentage of decrease in loggins, with the same number of accounts. It would be hard to determine the exact percentage, but it might be significant.