Why can I not choose Unearned Revenue as an account on items?

Why can I not choose Unearned Revenue as an account on items?

Hello, 

I do not understand why we don't have the ability to code an item to unearned revenue.  It is not an uncommon situation to have in business. 

I understand that there is the Retainer invoice as an option, however that doesn't really work for us.  Our customers are students in our band program.  As such, they have the ability to participate in various fundraisers, in which we issue credits to their account for the funds that they have earned which can then be used to pay for various fees, merchandise, instrument and accessories, etc.   You cannot apply credits toward retainer invoices.  And if I issue a normal invoice to apply the credit, that just defeats the purpose of billing in advance (we issue annual fees very early so the students / parents / guardians have ample time to pay, however these are budgeted for the next school season and need to be reflected as such). 

I also have the option of going into each invoice, and MANUALLY OVERRIDING the GL account.  Why have this functionality to begin with?  If you are giving a user the ability to force override the item account coding, why not just allow it go wherever you want it to? 

I do not have any intention of manually creating 3 invoices (different fees, different due dates, all for next years budget) for each of our 200 students and overriding the account coding.  I can't upload a csv for invoices and manually override. 

For goodness sakes, just let me pick the GL account that I want to in whatever module that I want to.  Add a popup if you must.  But if it's proper or not should be between me and my auditors, not Zoho.