Sounds as though you've discovered a version of the Combined knitting style for yourself. If you wrap the "wrong" way when you purl, the stitches will be twisted. You compensate for this by doing your knit stitches through the back loop. This is the standard way of knitting in many cultures.
As a result, you get the benefit of a much easier purl. Many people also find their purl rows are neater and more even when they knit this way.
The bottom line is: there are many ways to knit beyond standard English and Continental. If you are getting a good-looking stockinette fabric without twisted stitches (unless you want them), stay with it.
For more information on Combined Knitting:
In Mary Thomas's Knitting Book, which describes about a dozen knitting styles, look for "Eastern Uncrossed."