You may try removing the guard on mower discharge and allow the mower to blow the grass further from the mower.

I bought gator blades and they do a good job of dispersing the clippings.

I have the X534 with predator blades purchased from DEERE.The plastic mulch deal from DEERE is horrible,hard to clean and clumps in the middle, but good for cracking light amounts of leaves. I have a 54 with the deflector off ,and made my own deflector so I wouldnt get pelted by grass when it is windy, also keeps mower cleaner.I went out and bought some thin aluminum and molded it . Itook a while to get it just right but tin snips did the job.I painted it and it looks mint.Right now get those predators and try them out about 40bucks and sharpen them...
How high is your grass when you cut?

usually when any mower leave hay rows the operator is going too fast and cutting to much off IMO. Most likely your cutting too much off and even slowing down won't dispate that much grass being sheared off. IMO you've got some choices: slow down or raise the deck and over several cutting slowly lower the height of your grass till you hit the desired height you want, especially if you got a thick lush lawn, or get you a lawn sweeper when you want to cut real low all at once.

I'm not a big fan of removing the discharge chute or deflector. Especially if you have anybody in the area (including across the street when you mowing) why thoses blades are like missile launchers. anything laying in there path hard will be rocketed out the discharge exit. Which may cobob someone, worse yet any children, or bust out windows on house or cars going by.

That's why I never mow with my deck exit torward any traffic, people or parked cars. Acident waiting to happen IMO>

It is worth noting you should be mowing with the engine at full speed.

If not, that will help, though I think RCmoser is probably right.

Best of luck