No cater for wedding reception?

After cutting the guest list to about 60 people including the wedding party, I’m still running extremely close to my set budget. Now before, FH and I decided that since are wedding isn't till about 7pm with guest arriving around 6:30pm, we thought we would only have a very small reception, including just the cake and punch... Maybe a few candies scattered. Now, FH parents are deciding that it would be best to get someone to cater. I'm looking at 10-15 per head... that’s a minimum of $600. FH parents have been helping with providing the wedding along with my mom. They said they would go in halves with my dad. Now I don't talk too much with my dad, I know I want him to walk me down the aisle which he has agreed to. But should I feel bad about asking him to go in halves with them, or could I just stick to the way it was on only the small cake and punch? Would it be unreasonable of me to not want to have a cater?