To be honest.....that new c300 meltdown...to me would fit the bill.

I bought a hook in the box monster once.  Carefully placed it on the foul line and it didn't hook a bit, so I took it back. 

Seriously, contrary to common perception it is still the bowler who hooks the ball.  If this girl cant get a byte to hook all she is going to do with that ball speed is see a stronger ball hook a little bit in the heads, and then go straight. 

Also depends on why her ball doesn't hook enough.  If it is because it is burning up, then a weaker ball could hook more.  In the end, your trusted, local pro shop is who should be making this suggestion.

+1 even coming straight up the back of the ball the ball she will not get a stronger ball to hook "more"

IMO if she wants to see more movement down lane buy her a ball that will get down the lane easily then hook, and have her use the byte when she has real volume.

Actually, not entirely accurate. A lower rev player will commonly see their ball skid all the way to the pins. They don't have the hand to make the ball pick up even when it hits friction on the backend.
 
Some of these player can benefit from a lower RG ball with a high friction cover. Even though their roll is end-over-end, the cover grabs friction earlier, and provides more movement.
 
I don't know if this is the profile of the young lady, but it seems close based on the limited description provided.

I don't know how common or uncommon it is, but I see it frequently. I practice along side morning senior leagues on a fresh THS twice a week, and it's business as usual for many in those leagues. Crisp backends vary by house, and we don't have them....
 
I could note other examples, but the fact is that it's a situation many lower rev bowlers encounter.

At 13 mph, out of the box, a Byte should hook on anything with clean backends.  The comment I'm dialing in on is the straight up the back of it one.  If she's coming straight up the back of it, nothing else will hook more for her.  The Byte is a pretty aggressive ball.  Even at a 200 rev rate, which should be created by the natural rotation caused by even a weak wristed release, at 13 mph, a Byte should hook given even a moderate angle of rotation on just about anything.   

Based on your "clean backends" statement, I'd agree. The only point I was trying to make earlier is that "clean backends" are not a given. And while a NIB Byte is pretty aggressive, we don't know the current condition of her ball. Maybe it's a few years old, has 200+ games on it, and it's never been cleaned or resurfaced. It could be the reason the boyfriend is inquiring about something new.
 
So many questions, so few answers.   

I am 67 years old, have low revs, but medium ball speed ( 17 at arrows ).  I cant find a pattern shorter than 47 feet where I can get the ball to skid at the head pin even if I tried.   Possibly some people who throw a low track spinner might be able to skid the ball at the back end on todays conditions, but even with carrydown it would be rare.