Can we update conversion rate type for Revenue at Budget level in Grant Management

Summary:  Customer currently using 'Corporate' rate type in conversion rate for cost and revenue for budget lines in Awards, but now they wanted to use 'User' rate type, so is it possible?

attached screenshot for your reference ( You can see in which form we are trying to update rate type)

Content (required):Is it possible that, during the creation of budget for a project in Awards (Grant management), we can configurate a fixed exchange rate for all the budgets different to COP without affecting the execution and accounting of the projects. In case this is possible, can you please confirm that this kind of configuration is not going to make adjustments in the real execution or accounting?