After losing my Mammoth a while back, I went looking for a way to get another Cargohold Optimization Rig I built for its replacement.
The sticking point was alloyed tritanium bars, which currently run for around half a million ISK on the market.
The blueprint original I have for Cargohold Optimization required 100 alloyed tritanium bars.
50 million ISK for one set of ingredients alone. Too much.
While I was slowly collecting those bars by running missions (I have 34 total now) I decided to see if material efficiency could save me a little ISK.
The blueprint original I had been processed to a material efficiency level of 20.
To get it to a material efficiency level of 80 would cost half a million ISK.
If getting to 80 would cut the bill or materials by even ONE alloyed tritanium bar, it would pay for itself.
So I queued up the blueprint and waited.
After a 30 day wait, I got to see if my bet paid off.
The answer is: No
At material efficiency level 80, the blueprint still requires 100 alloyed tritanium bars.
So the jump from 20 to 80 does not change your bill of materials by even 1%.