Unfortunately, this isn't accurate, as QBO allows either hours/minutes or time in decimals when entering time, so you can ENTER time in tenths of an hour, and it will show as such when you enter it, when you save your timesheet, and even when you review your time entries by Customer.  It isn't until you generate an invoice that the QBO system inexplicably converts those time entries into a format used by virtually no one paying on an open invoice:  HH:MM. A solution I found is to generate an invoice with the HH:MM entries in PDF format, then use Acrobat to edit those entries.  That will allow you to send clients an invoice that looks like it should, and the time will still track with what is in the QBO system, so the invoice balance will stay consistent.  In my view, there is no reason QBO should be converting the time entries into a never used format for invoices. 

Hope this helps!