Reading data with different but similar semantics
As with all performance related questions, if and only if you can gather profiling evidence that shows that your current code is meaningfully detrimental to performance, don't call the first method in the second one, but rather repeat the code. This goes slightly against DRY (just barely, considering the very short code), but you will have to weigh the value of maintainability vs that of whatever performance gain is achieved.

In practice, I suspect that the effect on performance will be negligible if not non-existent. It's not as if you're not calling a slew of other methods and properties anyways.

The key point is profile profile profile.