Certifying your command will not solve the issue. For now you will have to do it either by adding sufficient wait times between workflows so that cache is updated or use a refresh command in your workflow to get the data currency.
BTW the upcoming release of WFA, will allow you take care of reservation even in case of custom commands that aren't certified.
Could you describe why only certified commands perform the reservations and not custom commands? It appears the only difference between the one that comes with WFA and the one I create is the certification.
The reservations have to be written for the custom commands based on what the command does. These are SQL scripts and one needs to understand the database schema to do this. This cannot be done for custom commands currently.
As Adai mentioned, the upcoming release of WFA will allow you to associate a SQL script with your custom command which will handle the reservations. Hope this helps.
Is there a specific release date for the next version of WFA? The workarounds regarding wait times or forced refreshes aren't realistic for an environment with any sort of high change rate -- a release date would help us plan for when we can start using WFA in a realistic manner, thanks.