When I first got my Infiniti G20t at 191k I changed the oil out at 192k with Castrol GTX hm and a Bosch filter back in April. Fast Forward to August at 196k I did the 2nd change. After the change I went to the local auto part store to recycle my oil. What I noticed was the oil was a light brown color not the usual black that I see sometimes. Was wondering if a 4k interval was ok or should I follow the manual and go for 7.5k interval?