Equipment Project Display
It's not possible to enter Customers, Real Estate or other accounts for the current job, in Equipment Hours records, where an Equipment account is being used.
User bug report.
If you enter Equipment Hours and job cost it to an account, it will show up in the Equipment account. You just can't enter it directly.
Fixed in version 3.8.
We recently added those fields, and apparently didn't finish all of the display details.