I'm not sure what you were asking them, unless it is that they ask you to wait at least 45 days before enquiring about the progress of your green card production.
You can also "bet" they need the fee. Card comes approx two months after POE or payment of the fee, whichever is LATER. So it doesn't really make a difference if you pay as soon as you arrive, but they will NOT produce the card if the fee has not been paid. But I'm not going to keep debating with you, pay whenever you want, just remember that you need the physical green card by a year after entry, and that if things go wrong in the production process it can take months to get that sorted out (partly because they have these rules eg wait 45 days after entry, wait 60 days after last enquiry, etc) and get the card to you. If you're happy to risk multiple delays, good for you.