It's not hard and fast with the 2 hours, but if you go too far over it they won't do it.How you were able to play & test it for 3 hours straight since Steam's refund policy is less than 2 hours as stated below:
"The Steam refund offer, within two weeks of purchase and with less than two hours of playtime!!
You need to give good reasoning and evidence, and I think it also depends on your Steam account and play activity. It said 3 hours by the time I refunded, so I took a shot.