complex restricted field access problem

I have posted a demo file for some feedback. I need to lock data entry in a field depending on user privilege. privilege from low to high is user1 (level 1), user 2 (level 2) and admin.

Level1(user1) can only enter the data but not sign the checkbox. Once user2 signs on he can change the data (if necessary) and sign the signaturecheckbox. Checking the box is irreversible. These restrictions are accomplished by privilege sets validated by an empty checkbox. user1 can only enter field (order) if signature checkbox is empty. As a final step once user2 signs the checkbox I want to give a limited amount of time to make revisions and then the record is permanent. I created a timestamp when the box is checked. timelock should automatically turn to 1 when the elapsed time has passed. As a test this is set to 40. When timestamp changes to 1 user2 is locked out of the fields by privilege set validation. However, when testing this after 10-12 seconds the field locks out for user2. It should wait until 40. Anybody have any ideas? let me know if I should explain more.

sigdemo.fp7.zip