I think it can be a little confusing. I have brewed a number of batches with what seems to be becoming an extinct method of brewing. It was sometimes referred to as the 1-2-3 method. 1 week in primary, 2 weeks in secondary and 3 weeks to condition. I have gotten fantastic results with this method, however, new thought is leading more and more people to essentially skip the secondary phase and let sit in primary for at least 3-4 weeks then go directly to keg or bottles.
I now use this long primary method of brewing because, for me, I feel it minimizes potential oxygenation and bacterial infection by eliminating a racking step. It is also easier (requires less steps) and lets the beer clear more quickly because the cake on the bottom is not disturbed.
The old method has been used fo rmany years and many still use it and fantastic beer is made this way. However, there are enough reasons for me to say I like the primary only version. So you decide, but either method will not be responsible for poor tasting beer, it still in my mind comes down to using good fundamental brewing principles (ie. sanitation, hitting mash temps correctly, chilling quickly, aerating properly, fermenting temps, yeast pitching rates, etc.)