PayPal new sign-up's limit

Just want to know if anybody else has experienced this as well. I have been using PayPal for some time. When a customer pays via PayPal for the first time, there's a US$1,000 (previously US$250) limit before he or she confirms his/her membership (a complicated process that usually takes more than a month, believe it or not).

This has been okay since most of my customers will probably not buy another item right after their first purchase. But yesterday, when I personally assisted a client of mine by the hand to make a payment on-line, it did not go through and kept asking for membership confirmation for just US$625. I helped check his account and the remaining limit was still US$1,000.

Any PayPal merchants know something about this? Please share it here. Thanks.

(A little disclaimer: I do know that PayPal sucks, ProPay is better, and it's always better to get a merchant account; but being a start-up in Canada, I'm deprived of both latter.)