4-5 hours of watering is way too much for any type of application method, be it drip, rotors, MP rotators, or sprays.
I'm curious what type of heads you have. Your overwatering could lead to Zoysia patch fungus.
Sometimes sod will go into shock if it sits on a pallet too long. Be diligent and patient with it... it will bounce back. Zoysia may take 2-3 weeks to recover as it has a slower metabolism. I've seen Bermuda recover from a straw look to emerald green in 7 days.
Yank up a piece of sod and look for new root growth. You'll see small white roots starting to sprout. If you see those, you're definitely going to recover.