Interest on quarterly contributions

[Guest Dan Moore]

I have a question about what Prop. Reg. 1.430(j)-1 says.

Say you have a plan where the sponsor puts in $49,800 on 4/15/2008, and then the 2008 quarterly requirement turns out to be $25,000. So, they've put in almost double.

Do you (in effect) get to credit interest on the extra $24,800 to 7/15/2008 (say the effective rate is 6%), so that you can skip the 7/15/2008 installment, or do you have to put in $200 by 7/15/2008? If you think you can skip 7/15/2008, where in 1.430(j)-1 or its preamble, for that matter, does it say you can? Thanks.