My take on a post from Kano a long while back:
The 5Nd "ramp" means it takes that long to reward your shares. It's not a punishment and The ramp isn't missing rewards, it's delaying them to reduce variance. Each share is rewarded in all the blocks found in the 5Nd after the share. That's simply how it reduces variance. Each share's reward is averaged out over the 5Nd after it.
How do the PPLNS payments work?
The 5Nd means the pool rewards 5 times the expected number of shares each time a block is found. So each share will be paid approximately 1/5 of it's expected value in each block it gets a reward, but each share is also expected, on average, to be rewarded 5 times in blocks found after the share is submitted to the pool.
So, on the 1st block the pool hits when you start on Kano you get rewarded 1/5 of the value of the shares you submitted for that block. On the 2nd block the pool hits you get 1/5 of the value of the shares you submitted for the 2nd block plus 1/5 of the value of the shares you submitted for the 1st block. On the 3rd block the pool hits you get 1/5 of the value of the shares you submitted for the 3rd block plus 1/5 of the value of the shares you submitted for the 2nd block plus 1/5 of the value of the shares you submitted for the 1st block and on and on like that until all of the value of the shares are paid. That's also how you would continue to get payouts for the 5Nd ramp down period after you leave this pool.
This is a simplistic view of 5Nd because it is also affected by luck. If pool luck was always 100% then each share is expected to be rewarded 5 times.
If pool luck is better than 100%, then the average share reward will be better than 5 times. (Love it when it hits 10-12 times!)
If pool luck is worse than 100%, then the average share reward will be less than 5 times.
The 5Nd really helps you out if your miners go down for a couple of hours or are down for a day. You would continue to be rewarded if the pool hit a block while you were down. I've seen pools where you would get nothing out of a block if you were down for just an hour or so when the block was hit.

The 5Nd windows isn't affected by luck. Whats affected by luck is how many solved blocks fall into that window.
@Vene if you look back a page or two I made some really simple pictures. But to be as simple as possible, when this block was found, it looked back at roughly 15 days worth of stats to determine payouts. Since you've only been mining for 3 days, your payout was smaller.
A really rough calculation would be (37/49091)*(3/15). This would be (your hash rate / pool hash rate) * (how long you've been mining here / current length of 5Nd "ramp")
But this calculation isn't exact because your hash rate and pool hash rate both fluctuate, how long you've been mining cannot be more than the length of the 5Nd "ramp" and the ramp itself changes length in terms of days when network difficulty changes.
Also important to note that the bitcoin you may be thinking of as "missing" are really just delayed. If you stop mining now, and we hit 3 blocks tomorrow, you'll still get paid for them since there is also a "ramp down".