When using adjuncts, like rice, it is important to look at the diastatic power of your malts. You want your mash to have an average power of around 40 Lintner for good conversion of starch. Your recipe uses pilsner (DP of 60) and munich (DP of 40) to convert a large amount of rice (no diastatic power). As mentioned above, if you mash the cooked rice with six row (DP of 160) you will get better starch conversion which means a more fermentable wort. Interestingly, the enzymes will convert the starch in the rice into maltose, just like it would with barley.
-the diastatic powers listed for the malts above may not be 100 percent right, but I think they are close. You get the idea.