Er, no, actually.
Up to 2004 , I think, you could just remove the spacer to get more travel. The damper unit was the same for all travels. After that, the dampers for different travel forks were also different lengths. Probably more expensive to produce, but at least you had to buy new forks more often!
On later forks you can reduce travel by fitting a spacer, but not increase it.
If you're only getting 70mm, there's something wrong. It's worth stripping them down and investigating. There are some good guides online. They're one of the easier forks to work on.
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Give a man a bank, and he can rob everybody.