I really don't think it's a temp and or time issue.
I went to answer the door once and couldn't make it back to the "darkroom" on time. The film was in the dev for about 30 sec longer and the temp was probably 3 or 4 degrees off. The images on the roll (Portra 800) ended up being ever so slightly off balance, but was very easily corrected in photoshop and in the enlarger using the filters.
Make sure you mix the chems directly as the instructions say. Last time I checked, the Tetenal kits specifically told you what order to put the mixtures in.
Mix another batch and tell us how it went!