Student or Learner
The certificate’s coverage periods should be checked and the owner must be given the opportunity to replace the policies should the contractor allow the policies to expire, with a back charge to the contractor for these expenses.
This phrase sounds odd to me. what does it convey? I can understand the part in bold but not the rest.
Pope of the Dictionary.com Forum
This is fairly sloppy writing in that there is no mention of who will check the coverage and when that coverage will be checked. At a minimum I would replace "should" with "shall" and replace "must" with "shall".