Lead Assignment rule not working with custom field.

Lead Assignment rule not working with custom field.

Setup a hidden value on the web-to-lead form, called "assignmentval". Created custom field in the lead module named "assignmentval". Put small section of PHP code in the web to lead form to generate a random number of 1-20 for assignmentval.

The values pass correctly, 1 through 20, totally random from lead to lead. Great.

Created assignment rule (named random), first rule is if assignment val is <= 10, assign to user A. 2nd rule was if assignmentval>=11, assign to user B.

All leads are being assigned to user A no matter what, even though the right assignmentval numbers are being passed through.

What gives?