Dark color tiptronic fluid... what does that mean?

[evo-r]

I've noticed some fluid leaks near tranny but can't identify exactly the leaky spot yet so yesterday I was checking the tiptronic fluid level and I had to add roughly 1 liter at that proper temperature range. I did notice the tip fluid that dripped out was dark. My '03 has 78k miles and I know I'll do a complete tranny fluid/filter replacement soon but in the mean time should I be concern with the dark color tip fluid? BTW, the tranny shifts fine.