Does the average power consumption while watching a YouTube video vary at different times?

Hello, I frequently monitor the average power consumption of my MacBook Air using an application called Coconut Battery while watching YouTube videos. I've noticed that for any particular YouTube Video, the average power consumption at a given period differs quite a bit from that at another random period. For example, when I watched a particular YouTube video this morning, the average power consumption was between 4.9 Watts and 5.7 Watts, but when I watched that same video this evening, the average power consumption was between 6.15 Watts and 7 Watts. This appears a little startling to me as the average power consumption in the case of other activities like light browsing of websites or running offline applications is more or less the same at all times.

Is this due to the difference in online traffic at different periods of the day, or is there any other factor(s) that contribute(s) towards this observation? Please explain this to me as I'm very curious to know.