As of my knowledge, you can't make any condition type mandatory in info record//
Time dependent condition is used in info record. And the calculation schema is used for time independent conditions..
We can't use time independent condition for info record.
But you can make these condition types as mandatory at PO level for the certain vendor..
Check the document to make the condition type mandatory for particular vendor.
Freight Charges or Discount Mandatory for Particular Vendor.
Regards