I will give it a try and maybe you should try the one I am using to see if it makes any difference.

Ok I downloaded it and gave it a quick test. I had more errors with your app than mine. 3 times the app drew the crazy long lines. Only once with Draw and Share. One thing I noticed is if you are gently with they stylus it is more prone to draw crazy lines. When I was firm all the time it worked ok. Too bad my hand writing is so bad in general. Not scientific but worth a try. Draw and Share does have a nice undo feature.