Manual completion of videos / Allow arrow-skipping

[Short version: Add an option (button/checkbox) to complete videos manually and/or allow skipping through a video in 5s intervals using the arrows. Alternately, allow skipping a percentage (~25/50%) of video content.]

So like many others, I like to skip back and forth in the video content, repeating sections I find difficult, and skipping sections to which I already know the answer. Personally, I need this freedom to suit the content to my goals, time constraints learning style.

However, apparently this is incompatible with the current 'completion-criteria' of the site. I get incomplete in videos where I know I've gone through all content, but may not have done so chronologically or missed tiny bits, e.g. I skipped back 10s and skipped ahead 15s.

Or I watched Sal write up a problem, paused the video, figured it out, then skipped ahead to see if I got the solution right; and if I didn't, skipped back and went through it step by step. 

This should not count as incomplete. To me, this is a dynamic approach to learning, and one of the great things about Khan Academy is the ability to have flexibility and great content at the same time. As a community, skipping sections we know well to focus learning on the parts we find challenging should not be discouraged, but rather encouraged.

So my request is this: Please consider changing the completion criteria to allow for at least a portion of video content to be skipped. 50% seems reasonable, as it would mean you can't simply skip through the entire video (for whatever reason, say, looking like you did your homework), but you can still skip sections without being penalized.

Alternately, add a button or checkbox option that can be enabled in account settings (add a password if you think parental controls relevant) to allow users to complete videos manually, without having to sit through an entire section of material again just to get a 'complete' status.

You would help all of us learn more in less time with greater satisfaction.

Thank you for an otherwise great site and outstanding content.