This is a balance of your market worth, and your value to the company. Your level of effort and expectations are secondary.
If you are substantially under your market worth, and the company is happy with you--you may be able to lean it. You'll want to raise the issue gently so you can get a "no" and stay without tarnishing yourself. For instance, it's okay to ask out of curiosity if you'll still be in an annual review, or what the normal process is, if the annual review is used to give warnings, assign bonus/raises, etc. Ask without asking if you can.
If you are at your market value or your company is still unsure, asking is risky. It sounds like you are at your market value, and being patient may help to get a bigger raise when the normal process comes around.
(For completeness, if you're over market value or your company isn't happy, don't push the issue--pushing a decision could cost you the job. This doesn't sound like your case.)
Doing a job above what you were brought in to do is fine. Many promotions happen because people start taking over tasks above their pay grade. Consider this: imagine I told you that you have two choices. One--you can do the work above your pay grade for a year, and then there's a much better chance that you'll be promoted and recognized after that year with more money. Two--you can do the work at your level, and hope to be promoted and recognized next year based on the performance at the lower level. If you'd choose One, then you're right where you would be.