i don't know what it might mean, technically, or physically, really.
I just take it to mean that I should not expect any quick dramatic results but to let it run a few days while it interacts with the phone hardware and software and my usage patterns and let it have a chance to show if it is going to work well with my phone.
Some folks, with their phone, get a kernel and it really works well for them.
I can get the same kernel on the same rom, set it up like they do, and not get the same results that they do, because, somehow, the phones are different.
Don't know if it is a hardware thing or just what apps I might be running, or the strength of the signal where I spend the most time, but the kernel just might not suit me. and vice versa, as well, I might swear by one and they be swearing AT it...