In general : i update
input type='text' data-number='true'
to
input type='number'

(looking at your first screenshot)

With good step etc ....
A plugin idea (for me)

I'm building a release version for my survey which prompted me to look at this again. In going through the template code, I found this is in bootstrap-slider.js, line 749.: Notice value: 5

Setting this to 0 fixed the issue.

Is there a reason why this would be 5 instead of 0?