On the other hand, I just got a 2014 X360 and the tech manual is $205. That's where I feel the price is unjustified. The X360 is a lot less complicated than the 1025. A lot of the stuff on the X360 I can figure out on my own or with the owners manual. There's just not a lot to the tractor, so I have to justify whether $200 is valuable to me. I figure the manual would be valuable for the engine or transaxle but that's about it for the most part. I'm still debating whether I should get one or not.
For your X758, I think you have to justify the cost yourself. Personally I think the machine is complex enough, like my 1025, that $160 is do-able.
Just my 2 pennies.