SDL 2.0.7 touch on Windows

I have a problem with FPS rate dropping before & after using touch on the Windows device. When a touch event is occurring everything is okay, only at the beginning and the end of touch event noticeable drop appears (e.g. at the start and finish of SDL_FINGERMOTION one can notice a drop from 120 to 99 fps or from 60 to 48 fps). At first glance, I thought that it’s caused by the fact that SDL handles both touch and mouse event simultaneously by default, so I added the following line to my code:
Unfortunately, there is no difference at all. The only solution is to set a constant framerate smaller then your PC is able to render in order to provide a smooth experience. Interestingly, turning on VSync also results in drops, even though the machine can handle much higher frame rate than 60 fps. Do you have any idea what could be done to avoid this annoying drop in fps?
Thank you in advance for your answers.