Many times our clients would like alternates included in a subcontract so items and prices are locked in if they choose to go with a different product or add additional scope. There should be an area these can be added into Sage Construction Management and then a mail merge table should be available to populate this information. This would be consistent with industry standard subcontracts.
As it is we have to print the template and enter it all by hand and then the Sage CM subcontract doesn't include all the relevant information.
Have you reviewed the Allowances feature in the Client Contract Admin Module? This would apply to the Project Owner, Homeowner, Client or Customer. Are you asking for similar features related to Vendor Subcontracts?
https://help.sagecm.intacct.com/Content/Modules/ContractAdministration/AllowancePackage/AllowancePackageOverview.htm
https://help.sagecm.intacct.com/Content/Modules/ImplementationGuidelines/OwnerContingency_Commercial/Implementation_OwnerContingencyCommercial.htm?Highlight=allowance