Business is having the need for Approvals to rewards team based on Other Compensation plan value

Business is having the need for Approvals to rewards team based on Other Compensation plan value in Job Offer Section.

If Value is >= 15000, then rewards team should be the first approver and remaining approval chain follows
Else, Rewards team should not be in the approval chain

Challenge here is Attribute for this Other Compensation Value is "Other Compensation Details.Value" not having an option to enter number, This is having options to Enter String, Boolean, Function. Configured approval rules are below:

(Proposed Assignment Details.Country == "GB") AND ((Other Compensation Details.Plan Name == "Sign On Bonus") AND (Other Compensation Details.Value < "15000"))