Blah blah blah - Why the disposable equivalent is greater?

I ordered these blades with the razor that goes there a few months on Amazon. I come from a simple Mach 3 but have tested all versions thereof as well as the 1st Merger of competing brand. Note that I shave my full, crane + beard, mostly to the skull length of a week, and every 2 days for the beard.
I shave the skull in the shower with mostly shower gel and beard with shaving gel (currently the Wilkinson).
If the system that rotates to shave under the nose is very convenient, it is the only thing that can make me love this razor.
Shaving is less accurate than my old blade, I'm go against the grain under the throat, shaving is never clear. Also every time I micro cuts in the face or throat.
In addition to the product that is above the blades goes from a little water over lands (the blades are in their carrier left my sink). As it is marked to be changed as soon as a blade hole is visible at the product, I should throw my blades without using ...
To date, "expiry", as indicated another comment, I hope it is rather to the date of manufacture 02-2014 because for me, bought late March early April.
In short, not convinced by this product, if not by its price, very competitive in abo Amazon.
But the strongest is that a few days after ordering razor blades +, I see in my equivalent hypermarket Disposable promo. I say "hey I'll try", as I was leaving abroad, convenient to carry.
And then, surprise, shaving at least equivalent, see higher and everlasting razor. I use the same for 2 months to shave the skull in the shower, putting the finishing thereafter with new blades.
So, I expect to find the disposable model to make a promo stock ...