Wow! What an excruciating effort to define the concept "benefit".
Here's a thought which I haven't picked up on thru the thread, how can it be an "assumed" benefit? For something to be a "benefit", the SR needs to know something about the prospect's specific needs. "Lots of dealers can sell me a car with 'different benefits and features'....I will find the one that solves my problem the best way for me." Different features perhaps but without understanding your specific situation, (without probing specifically) what different benefits are imaginable? I've walked onto the car lot and been accosted by SRs flogging a 2-seater but with 2 kids, that simply was not on-the-table.
As you probe, you uncover myriad topics which are juggled until you get to a point of clarity. Typically what has happened is you've uncovered benefits of your offering. "Benefit: a sufficiently positive advantage/improvement to be acknowledged by your prospect."
At this stage, (if you're SPIN-trained) loop back to find more situational details, problems, implications, etc. Or, you begin to direct the discussion towards uncovering more appealing benefits of your offering (not a "features spray"). Once you've gained a comfort level that you have sufficient to rationalize the sale, you re-cap the agreed upon benefits and work towards the close.
KEY: It's NOT always needs, problems, or pain which are the foundation for a decision to buy. If you're an astute SSR, you'll recognize opportunities which imply meaningful advantages for your offering (massive ROI, future business direction, competitive edge for your prospect, etc.). These topics might not have been on the horizon ...
Good luck & Good selling!
Pat