Not necessarily. Your present arrangement offers a single, large pool of addresses. I'm assuming that you only have a few PCs since your consultant is suggesting that you use a smaller range for their addresses. The idea might be to slice your current IP address range into a series of smaller ranges. There are several reasons why you might want to do this; to implement separation using VLANs, to introduce routing between buildings or departments, to pave the way for moving a whole section to another location etc. The only question in my mind though is why such a small range for the PCs? Perhaps, if you have many PCs, your consultant is suggesting splitting them up into groups too, in which case their IP addresses will also need to change
