Your not wearing it all the time
so skip the Second Chance and find a cheaper vest. The Second Chance vests are some of the best, and some of the most expensive. If you wear it every day that's a great way to go. But for a part time job- it may just not be worth the $$- you can save a lot of money (2/3)by going with a Galls vest, an Extreme Armour, or any of a dozen other manufacturers for 1/3 the price. The low cost has a trade off, weight and bulk. The less expensive vest will weigh twice as much as a high-end vest, and be several times thicker. But they will stop a round just as well as an expesive vest. You can even get a higher level of protection then you could with the expensive vest and still save a lot of money.
If your an LEO who lives in your vest (I am) then the Second Chance is the cats #^%, but if you only need it a few hours a week, spend your money on a level IIIA vest from someone like Extreme Armour (about $350) and take the $700 you saved over a 2nd chance and buy some toys.
Of course this is just my very humble opinion, you do whatever the heck you want, it is your money.