As a few have mentioned maybe it is a combination of factors. I store the Dektol in the garage/darkroom where it can get up to 85 degrees in the summer and down to 55 degrees in the winter. But I store my paper in my bedroom where it is a consistent 70 degrees year round. Maybe I might be better off using a liquid developer like Ilford Universal (concentrate) and just dilute right before printing using distilled water . I used it for the first few months and changed to Dektol for some reason even though I was happy with it. Also I will try to be more consistent with the developer temperature having it vary only a few degrees. Believe it or not I don't have a regular light meter. Just the MR meter that attaches to the Leica so it might be more difficult to judge the enlarger light. If I remember correctly when I attempted to duplicate a print over the weekend it came out darker with very slightly more contrast. In the past I can't quite if the prints were darker or lighter.