It's tough to answer, and you will have people looking at it either way they want.  HOWEVER, I think the most important fact here is last year's average.  If you averaged 232 last year, you must have put up some numbers.  And in averaging 232, I'm sure that whatever the handicap was, if you hit that average every game, you would be ahead of someone getting handicap and hitting THEIR average every game.  So while someone may say you're using plastic to sandbag . . I see it the other way.  Obviously you have much more of an advantage bowling to your potential.  Now I'm sure you'll pop in a pretty big game once and a while, but if I could count how many times I've heard it announced at the bowling alley that so and so with a 150 average shot 240, I'd need the legs of a millipede to add it all up.  And averaging that high on a house shot with reactive equipment gets old.  It's not fun like people think it would be, the only challenge you have week in and week out is carrying, that's it, and that's for all intents and purposes out of your hands, it's nothing you have control over to improve.  It really feels like you've gone as far as you can, so you start looking for something else to spice it up a bit, or to change, a fresh challenge so to speak.  If I had to guess, I'd say that's what led you to plastic. 

Most tournaments take the higher average of the last two years.