Yup, the ramp up process is still there when you add another one. Its up hill.. then when you get to the top, its a little bumpy, depending what the block rewards are, but you will come out ahead of any other pool. Here you get those transaction fees rewarded to miners. Plus its the lowest fee of 0.9 percent ( 0.0 ) until 2018, which is a few hours, but hey, where else do you see that kind of stuff in the bitcoin world.....
I started with 1 S9 on Dec 10, and just a few days ago got another 4. I thought it was a good way to heat my house and garage. :-) What kind of heater PAYS you to use it?
FYI The easiest way it can be explained, that I can think of is, that red area on the Workers Shift graph is a moving window. You get paid on the percentage of the shares you contributed to the total. So just hover your mouse over the left side, and you will see the date at when the window starts. if you were mining on that day and time, you are ramped up. If you started somewhere between then and now, your average is less over that full period of time. BUT never fear, if you stop mining at kano ( and you know you WON'T :-) you get that ramp down the same way the ramp up was. Except the percentage of the shares for the period was going down, so the payouts will decrease as that " window " passes.
Hope that made sense.