I didn't notice that you edited it away.
If an IP address is statically assigned on the device (=printer for instance) this IP address will not get excluded from that pool and may clash with it! That device doesn't use DHCP and has a "real" static IP. The router doesn't know anything about it. Nevertheless, it works like a normal IP address as long as the router doesn't try to assign the same IP address to another device (and it does that because it doesn't know ... the circle closes here). You can circumvent this by switching that device to DHCP and assigning a manual IP address on the router. As you do for the PCs. Same procedure. But you don't have to if it is guaranteed there can't be a clash.
If an IP address is assigned "manually" (manually is a good term to distinguish it from static) on the router it has to come from the dynamic IP pool range, of course. It's that range that the router controls. The manual assignment on the router is not a "real" static IP address. It only tells the router to always keep assigning this address via DHCP. And it can only assign what's in its pool. That's why you can only assign an IP manually that is in that pool. Everything outside this range is for use on the device (e.g. you switch off DHCP on the device and tell it what IP address to use) without any router intervention.
Your first advice was good. I hope your clarification doesn't confuse Roger. ;-)
Roger, the IP pool range doesn't matter. If you have only two devices a range from .50 to .60 (ten numbers) would already suffice. Tell us the current IP numbers of all your devices on the network and if they are on DHCP or not and we can tell you if you should change the IP pool range. If I understood correctly you have at least four devices on the network: router, printer, two PCs.