checkout_success is showing wrong order with Paypal Standard

Good day!
I hope this is the right section and I have searched forums for solution to my problem, unsuccessfully.

SO, payment module used is "PayPal IPN - Website Payments Standard".
After client is redirected from paypal having successfully paid for chosen product the checkout_success page is shown for previous product not the one that just have been bought. After page reload everything looks fine and order history is OK. Looks like the order insert query is happening after the page is loaded. I've temporarily put sleep(1) in a header of checkout_success and it works but there should be a better solution for this. Any thoughts please?

You have 4 options:

1. Use what you've got with your customization.

2. Use Express Checkout instead ... Express doesn't have to wait for PayPal's server to talk to your server in the background to tell it of the new order.

3. Rewrite the whole way Zen Cart and the PayPal IPN module work so order details are handled differently.

4. Call PayPal and get them to make their communications from their server to your server faster than it already is. While you're at it, get your hosting company to speed up their connection to the internet and speed up the processing speed of your webserver.

I vote for #2, or if you don't like that, use #1.

Well, surely #2 is the only realistic(not counting #1) for me, I think I had some problems before with Express Checkout but I'll try.
Thank you very much for your answer.