I found the same thing. The cheeks and some parts of the neck are easy for the blade to shave the stubble. The chin and mustache are where the rubber meets the road. It takes a truly shave ready razor to cut those whiskers.

It takes some time practicing to get to where you can hone a razor to shave ready. It is good to have at least one honed by a pro to give you a benchmark for what a shave ready razor will feel like.

It should go through those chin whiskers like a hot knife through butter. I got lucky in that I had a honemiester living nearby and he showed me a lot. That, a severe case of RAD and a lot of patience and persistence got me to where I can get them sharp. If you can find a forum member near you who is experienced in honing and will show you that is a real +. One way or the other keep at it and you will be having smooth shaves before too long.