When you're deciphering alchemical texts,it actually is hard work, especially when you're trying out the recipes to make sure you know what you're teaching.
If you do your homework,you'll find out that most of the inconsistencies of Nick were when he was excited about a new process,and rambled on about his latest theories about what comes next. Then later on he would try the process a few times,and correct mistakes in those theories. (not unlike myself in many respects)