Champion Juicer Wheatgrass and Leafy Green Attachment

It is the most frothy with leafy greens, or soft fruit like orange, or beets. With carrots, apples, celery, ginger, lemons, and similar things it does pretty well. I do cut things up especially cellery since the strings wrap around the cutter if I don't. Is there any way to know other than the amount of use of a cutter to determine if it is dull. Is there a performance test of some sort where you can be sure, or is it if you are asking it probably needs it. How does the Champion with a new cutter perform different from one with an oler cutter? Since I bought it used I don't know the history of the cutter.

I also have a question about wheat grass, everyone seems to say the Champion cannot do wheatgrass, but in the manual it says WHEAT GRASS JUICE
Type of Vegetable to Use: Freshly cut wheat
grass.
Preparing the Vegetables: Cut the grass in 2 inch
lengths, 6 cups of grass yield 6 ounces of juice.
Feeding Process: Juice the wheat grass a small
amount at a time, alternating with a small amount
of water, until all is juiced. For a tastier nutritious
drink, add 6 walnuts and four cups of carrot
juice.

Is that considered different than the wheat grass people talk about?