jiahd,
It is not necessarily you, although at times it is the scheduler, at other times it is the software. Not all software are created equal.
Unfortunately I have not been able to find a true independent reference that is up to date and includes Spider Project, Primavera P6, Asta Power Project, MS Project and Aurora among others. An independent reference from a recognized institution.
I was among those who avoid resource leveling when was a SureTrak user, we found it to be not good enough for our needs, even P3 we considered not enough, P6 no way.
I have compared my software with a few others that claim to have the superior algorithm and my choice always won, at times by a wide margin. But it is impossible for me, as an individual to make a comparison using a selection of more than a handful of software, and not to mention the procedure that will make the comparison valid.
If you feel it is not you, then you shall investigate other tools.
Best Regards,
Rafael