Adobe Premiere CS6 Exporting File at Lower Size Than Expected

So, I was working on a documentary on Premiere CS6 with the following project specs

• 1920x822 (Anamorphic or Widescreen)
• 29.97 fps (might change it to 23.87 fps later)
• first sequence is 1080x822
• next set of sequences are 1280x548

And when I checked each sequence, each sequence has an estimated file size of (give or take) around 700-750mb per sequence, and when I made the final sequence (all the sequences put together) it all totals up to 5311MB = 5.3GB since this is a 37-minute video project.

The only thing that's really confusing me is the fact that when I finalized everything, saved the project, closed the editing software and went to sleep for the night -- but when I went back to the project this morning, I went to export it but when I was in the export settings, the estimated file size is now 1235MB = 1.2GB...

I'm really confused, I have no idea what happened on post production since I didn't do that much of a change when I came back to the project this morning. I mean I'm not complaining over the file size and everything (of course, everyone wants to preserve as much as possible on external hard drives being cluttered around) but I'm just confused.

The concern that I have is for the fact that the video project might be at a lower quality now...

OR maybe just the fact that I decreased the height from 1080 to 822, since the export settings are set to 1920x822...

Any possible answers or thoughts would be greatly appreciated...

Thanks!

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