Why this IP 192. 168. 174. 136 address changes in 192. 168. 174. 133 during pentest ?

HELLO.

I would like to know why in most pentest with Metasploit Tutorial I watched, I noticed that the IP address used are not necessarily those of the victims live.

Example: For a. ASP site which has as address normal IP 192. 168. 174. 136, I do not understand why bearing a grudge attack this IP (192. 168. 174. 136) address, the tuto shows rather other one addresses IP who resembles the start address only a bit: he used a new address which is 192. 168. 174. 133 instead of 192. 168. 174. 136 to go about things how is that is made?

Do you think that I do not have the right to write normal IP (192. 168. 174. 136) to attack a target ?

How to find an IP address similar to initial address IP as this one for example 192. 168. 174. 133 instead of 192. 168. 174. 136 to achieve my attack of pentest ?

Thank you for giving information to me please.