Inherited a model 455 - have some questions

I have a model 455 with a 54" deck. It looks like the deck has a mulching kit installed. I ran it for the first time today. I live in the Sandhills of NC, so named because that's what our soil is. That means that we really don't get much for grass - I usually say I'm going out to mow the weeds. Needless to say, my yard has a lot of dried debris in it. While I was mowing, the mower (and I) got covered in this debris. It seems like the deck isn't low enough to make somewhat of a seal with the ground and the blades are acting like a fan and blowing stuff everywhere. Is that normal? I haven't used a rider out here and the grass where I grew up in the mid-west is much different than out here.

If you were mowing at the cutting height you desired, than yes, that's pretty typical.