Let me first say that all of this is just my guesstimates based on my assumptions and should be looked at as my opinion only.
Let me answer #2 first.
The slide shows 100 machines in production in Orthopaedics
Arcam has about 239 systems in the field already, nothing to do with future sales. I estimate they have about 75 systems in Aerospace.......Let's assume 1/3 or 25 are in production.
So that would be about 125 systems
1 ton x 125 = 125 tonnes plus maybe throw in another 5 tonnes for those machines in research and proofing out parts, so about 130 tons.
Well again, the slide shows only about 50 tonnes used in AM industry - so we know Arcam didn't sell all 50 tons!
Based on that, we know for sure it is NOT likely that a machine uses 1 tonne of material, but something considerably less.
So for your #1
I think 250-300 kg is close enough, not trying to be exact......no need to imo.
The powder mix to customers is a fluid situation, there have multiple times that APC/Magnus has given the 40/40/20. If Arcam is now 50% so be it, I think Magnus was just giving a rough estimate and did not include the complete breakdown.
To me this is what the message boards are for......throw things out there to get other's perspectives. I have learned a great deal from these boards and would rather people say something, than say nothing.