Once again something I do not know if it is a bug or just some supidness of mine The commands sent via remoting are validated against the tform files of the interface. Quota entries are put in as MB in the interface forms, then validated against MB (max 7 numbers length) and after this converted to bytes (*1024*1024) and stored in the database. If you use the remoting lib to store quota, is this conversion done anyway? I didn't think so as it is in the interface xxxx_edit.php file. You cannot send the quota as bytes through the remoting either, as 7 numbers are too short (10MB * 1024 * 1024 = 8 numbers). This should apply to mail users (mailbox quota), ftp users (quota), web domains (quota and traffic) I think, but correct me if I am wrong or miss something.
Looks like a bug, the quota should be recalculated by the remote api as well. Please make a bugreport so we can fix that for 3.0.5.