In this study, we compare two different approaches to precision tuning --- worst-case static annotation, and profile-guided annotation. We propose and implement a profile-guided approach in an existing precision tuning tool TAFFO. In comparison to the static approach used by the tool before, the profile-guided approach reaches up to 4 orders of magnitude lower error while providing comparable speedup and requiring less expertise from the programmer, tested on benchmarks of the PolyBench/C suite.