"Is there something I'm missing?" Yup... He said "develop", not "expose"... ;)
But I don't agree anyway! ;) It depends on the paper and developer how long it takes to get a good black. Ansco 130 is much slower to get a black than Neutol for example and Ilford MGIV RC paper is 2 to 4 times faster to develop than the same manufacturer's FB. I generally use 5 times the first appearance time (the time when the shadows first start to appear on the print in the developer). I do agree however that consistency is a major key to success.
Easels are pretty well essential for fibre paper and jolly useful for RC - you can keep RC flat with a bit of double sided tape in the middle though as they tend to curl "upwards" in teh centre. If you want white borders, get an easel.