Increase Weight or Work on Form?

[aWalkingShadow]

If form is less than ideal, but the reps and sets were completed with ease, should one continue to increase the weight?

I currently have this problem with my deadlift. I have already performed a few resets in weight, but once I begin to approach to my old PR's, my back gets pulled out of extension and begins to round.

Here are my deadlifts. Back rounding is slight, but I can feel it during the set.
http://youtu.be/s2AAcFFLhEQ?t=21s

So, as I see it, I have two options.
1) Keeping working on form until my back is strong enough to remain flat, so that my form doesn't continue to degrade and so I don't get injured.
However, by not increasing weight, I don't get stronger and the back rounding might never resolve itself, since this issue seems to be one of strength as well as technique.
2) Increase weight to drive strength increases. We accept less than perfect form, but continue to make progress.
However, I risk having my form deteriorate even further, and I have a higher risk of injury, which would significantly derail progress.

What do you suggest I do?

[Poco journo]

Looked good to me. I say increase.

[bean counter]

OP, please pardon my interjection, but as I have the same question I thought I'd put it in this thread too. Your back looks flatter than mine.

http://youtu.be/NzLPOugCXyg


Thoughts?