How much difference should I expect between the database sizes reported between phpMyAdmin and cPanel?

The reason I'm asking, is I recently set-up a drupal multisite installation, but the databases seem to be excessively large when checked in cPanel, but not that big when checked in phpMyAdmin.
In cPanel, they're reported as 50.15 and 11.47mb, while in phpMyAdmin the totals are only 6.0 and 9.1 respectively.

I've checked a couple SMF sites hosted on the same server, and the database sizes on them are pretty similar between cPanel and phpMyAdmin.
One site is 24.34 v. 23.1, and the other 50.15 v. 48.8.

I've already contacted the host about it, and they say the discrepency is down to how cPanel and phpMyAdmin calculate the totals, but should there be that big a difference?
Or is it something to do with how Drupal is using the databases?