It looks like it may be up to the component on how they set up their procedures.
DoDFMR Volume 10 chapter 23
230505. Conditions for Using Convenience Check Accounts With the exception of contingency or emergency operations, convenience checks shall not be written over $3,000 for supplies, $2,500 for services, and $2,000 for construction. Refer to the DoD Government Charge Card Guidebook for further details regarding changes to these thresholds and convenience check use. In order to maintain effective internal controls, approving officials (also known as billing officials), accountable officials and certifying officials will not perform the functions of convenience check custodian or cashier.
A. Convenience checks will be issued for the exact payment amount, with a prohibition on splitting purchases, payments, or other amounts among more than one check in order to keep amounts below micro purchase threshold or other assigned limits.
E. The issuing activity is responsible for all administrative costs associated with the use of convenience checks. Fees associated with the use of convenience checks are specified in the GSA contract. At DoD Component election, the costs associated with the purchase of convenience checks may be: (a) accounted for as part of the purchase price; or (b) treated separately as an administrative cost of the issuing activity.