The dial is also in DIN with 24 25 26 27. On the normally accepted scale that is 200 (24), 250 (25), 320 (26), 400 (27).
Your calculations assume the progression in ISO is arithmetic, when in reality it's geometric. A one stop increase is always a doubling of the Iso/ASA.
The closest you'll get to 325 is 320 Iso / Din 26.
Film amateur with a few rangefinders - Leica III, M2/M3, Werra 3 and Zeiss Super Ikonta 534/16 medium format.
Apart from that have a Rolleiflex 3.5F, the odd Minolta XD7, Hasselblad 500cm, a Topcon Super D and an Intrepid 5x4 large format (not the half of it but I am clearing them out, honest).
I do all my own black and white developing at home.