Efuse on Grids

I want to learn more about embedded development so I decided to build my own grids module.
I’ve build a separate logic board and and will do the analog interface later. I run into some problems when I was going to download the stock FW to a brand new AT328p (in DIP) but after a couple of hours I got it to work.
My problem is to set the efuse bits. According to the make file the efuse should be 0x05 but I can’t program that.
When I look in a fuse calculator (http://www.engbedded.com/fusecalc/) I’ve noticed that the bits are inverted, 0b000 > 0xFf, 0b001> 0xFE etc.
Are the make file setting faulty?

The 5 highest extended bits are not used, so depending on the software you use, they can be set to 0 or 1.

0x05 or 0xfd will give the same results.

Somehow 0xfd works on my setup (avrdude 6.2 + ArduinoISP) but not 0x05.
My next challenge is to figure out how the ADC pins are mapped on the AT328P 28 PDIP vs. TQFP. From what I can tell the tempo(ADC6) is ADC5…