I have a max allowed download of 612MB at the moment.

I have a 234MB file that I intended to download. I was downloading through file manager and at 94MB it has stopped saying that the remaining downloadable bytes are not enough for this download. Please see that the downloaded bytes are still at 416MB leaving adequate room for this download to complete.

The problem I think is happening when I press resumes, I calculate on all the 234MB instead of using the partially downloaded file and then calculating remaining download.

Please note the free service is for personal and casual use only. Uploading / downloading files of more than 100MB is generally not casual use. I would strongly recommend upgrading to the premium service. It starts at only $29.99/year. Alternatively, you might want to try more DriveHQ features at:

http://www.drivehq.com/freeBandwidth.aspx

It will give you more free download bytes. Of course, after you try so many great features, we hope you sign up our premium service. It is not expensive at all.