Hi,
first of all, great idea!!
I did everything you wrote, but it shows an error:
"The Symbol 'HdTimeStamp2_CODE' does not exist."
Interestingly, there is no error with "HdTimeStamp1_CODE"...
Note:
I put the skip "(HdTimeStamp2_CODE-HdTimeStamp1_CODE)<300" directly in the TimeStamp2 question.
I put the text above in the Free Format Question in the "Advanced" Tab and then in "Custom JavaScript Verification" and
chose: call ..."after" ...verification.