Dude was trying to be helpful, and Command Center Upgrades V can offer more than a linear increase in isk efficiency, depending on what you’re trying to do (i.e. it can allow you to make more effecient factory planet setups on worlds with small radii and allow your extractor heads to stretch further in order to chase hotspots). But you’re right, I wouldn’t worry about it too much as a newbro doing PI in HS.
Anyway, it’s been years since I did any PI, let alone in HS. So take this with a grain of salt. But I want to say that you can make around 300-500mil a month. Also, do note that production across new eden has taken a nose dive, so demand for P.I. might suffer as well. Looks like coolant is still doing okay, but you should be aware of potential trouble ahead. Not saying you shouldn’t proceed, but if prices do take a nosedive, you might want to hold on to your stock, and then start trying to sell it again when production picks back up.