Does she use a mechanical release with her compound bow? One thing she will notice, as everybody else certainly does, is that there's no let-off with a recurve, like there is with a compound. The farther back you pull it, the harder it is to pull and hold. And the weakest part of your body is your fingers. It's not too hard to get, and keep, your arms, shoulders, and back in shape, but keeping your fingers in shape is much harder. With a mechanical release it's much easier to pull and hold the string, and get consistent releases. If you intend to use a mechanical release look into using a "release loop" on your string. The release loop gets chewed up, but it's easily and cheaply replaced.
Besides having more penetrating power, a more powerful bow shoots arrows with a flatter trajectory. That makes it easier to hit targets farther away. Less guess work. But if she can pull a 40 lb bow 28" she should be able to consistently put arrows where they need to go out to 30-35 yards.