Two Questions for Finance Whizzes, Please

<p>Thanks for any help in advance:</p>

<p>Scenario: Two bright high schoolers, two full-pay probables due to frugal living but still hardship for us-we have no state res due to overseas post.
slight chance of some aid(10,000 of 50,000?) when two are in for two years together, but don't want to assume.</p>

<p>1) Should we max our gift aid through PA529 (we are not in Pa therefore no tax break there)--present mix paying about 7% [72,000 from each parent=total $288,000)--am not sure if that would be spent, assuming 20,000 non-taxed interest annually and total 400,000 in college payments. Am I being too optimistic about returns here? It seems like Vanguard performs better than most.
Would it pay to just incur the penalty and loss of tax break at the end of their time in college?</p>

<p>2)What do you think of prepaying tuition? What are tha average rates of tuition increases at Ivys?</p>

<p>Thanks so much. (BTW, lots of merit aid but just not at the optimum fits)</p>