Some PoS implementations use limited time range let's say +-10 minutes in unix time seconds from time now as limited variable input into hash function. Something like nonce in PoW but in PoW nonce usually is not very strictly limited.
Yeah; in order to limit hashing speeds; the oscillator that the time function is based off of, would need to be very precise for repeat-ability; but the time function wouldn't be for something as simple as a nonce; it would be dispersed throughout the entire set of hashing functions.
The reason for the time based nonce is basically just to be another security protection against withholding blocks from the network.
And it cannot be limited too, because there's nothing stopping miners from mining to multiple address on the same device, using the same range of nonces.
you could; but; imagine the impact of my idea on a pool....... Suddenly; the large amount of hash is a bad thing... forcing decentralization... to a point.
I see how you could theoretically do the same functions on different addresses at the same time; but their results will always be different each round; and would need to be calculated individually; not linear-ally "through the same hardware pipe" so to speak; needing individual hardware for each.
this goes right in line with making the number of individual "devices" the core reason you would have more of a chance of getting a winning result.... making all devices relatively equal by limitations of time.