Electromagnetic simulations are an important tool for RF coil and thermal RF applicator development. For rapid design evaluation, fast low mesh resolution simulations would be of benefit, which can however potentially introduce errors in regions of intricate tissue distributions. We rigorously analyze local power deposition errors introduced by using low-resolution meshes in simulations of a highly detailed head model at 297 MHz. Our results indicate, that even at 5mm the introduced error is acceptable. However, artificial current paths are formed in the oronasal cavity, leading to not critical albeit locally elevated power deposition, thus deserving additional attention.