The Noun Assumes; the Verb Explains

The following sentence puzzled me:

"The investment account should have been [cashed in] second, given a long-term tax rate versus the traditional income tax liability."

That sentence advises a retiree when to draw from her investment account.  But that advice gets an "explanation" that fails to explain.  The "given that..." phrase assumes that every reader instantly knows which is greater: "long-term tax rate" or "traditional income tax liability."    

If the noun "tax" became a verb, the new sentence would explain the writer's rationale:

The investment account should have been cashed in second, because the U.S. government taxes long-term investment gains at a lower rate than it taxes other income.