We would never run any WAP over a dozen connections. You gone over 10 tens that. Nice idea, if it works but it didn't so if you believe this router can do that many connections then you know who to call next.
You also know that WiFi interference is common but I see no mention of that in your post.
There is a bug that seems to be in many router firmware versions and it's one I encounter a lot. I see no mention of where you tried the latest and a few prior versions.
I'll be honest with you, I would not expect that many connections to work reliably. There are many reasons since you have 50 odd computers and all it takes is one bad one to misbehave and knock others off the air. I mitigate that with more than one WAP.
Recently I installed an Asus RT-N66U router to serve a building that houses staff and some guests, in all about 50 people in a given day. By all accounts it's one of the best routers money can buy but we've still been having problems with it. I've been experimenting with it for a while to try and nail down what could be the problem but nothing seems to help.
The network is WPA2 protected and uses the same SSID and password as our company's other wifi networks in other buildings for convenience. Some devices seem to connect just fine - for others, sometimes mobiles sometimes laptops, when trying to connect users are told "Unable to connect to ***". Does anyone have any idea what could be causing this? The router is running on the latest firmware and DHCP is enabled, with a pool of 199 IP addresses. I thought it could be an issue with lease times but whether I put short or long leases, the issue still occurs sporadically.
Any help on this would be massively appreciated because I'm close to pulling out hair.