My OP12 doesn't charge as fast as advertised

It supposedly charges from 0-50 in 12 minutes from what I've found online, but mine charges for about 20% every 10 minutes. it's still pretty fast, but not as fast as I expected it to.

For context, I did just recently change my adapter because the one that came from the box broke. I plugged it in a restaurant's outlet and when I got back home, it threw a spark when plugged in and just wont charge. So I bought another 100W supervooc charger (from oppo because oneplus doesn't officially sell here).

These are the new adapter's specs: - Input : 100-240-50/60Hz 2.5A - Output : 5v-2a 10 w or 5-11 v - 7.3a (max) - Input : 100-240-50/60Hz 2.5A - Output : 2.5-2 OR 5V-11V=9.1A 100 Watt (max)

I'm at work right now and my old adapter is at home so I can't check exactly what the old one's specs are but if my memory serves me right, it should be the same. I also used an app called Ampere to check the current going in as it's charging and it was on average 2.8A (2800mA). Shouldn't it be closer to 7.3A or 9.1A?

I don't actually remember how fast it charges with the old one since i never actually timed it, but I timed it this time because it felt just slightly slower than before. Am I just being overly concious about this?