From the description I see on net this is indeed true, with big IF - you already have prior acclimatization to 5000m+. Without it, its almost impossible to make it to the top and back at that altitude, unless you have some super genes. And descriptions mention still 10 hours of hiking and altitude difference of some 1300m.

Even though the air around equator is thicker, you would most probably already feel very bad at the carpark at 4800m, if you would come up straight from the capital. I'd say some 5-7day acclimatization prior to this should be enough for most fit people.