Actually, that's similar to what I see for mileage on my CRD. I have seen as high as 30 to 33 on long interstate trips, and as much as 580 miles on one tank.
BUT.......
I've done quite a few mods to mine, to correct "issues" with Chrysler's (DaimlerChrysler at the time) bean counter engineering - fuel system, torque converter, etc.
To be honest, I wouldn't recommend a still-stock CRD as a primary vehicle - I went thru at least 3 grand in mods just geared toward getting it to where I felt it was reliable as a primary vehicle - I've owned a Subaru before (an '87 GL wagon I kept for 18 years), and you'd probably be better served by your Subaru as a primary reliable daily driver.