Consider the cost of
I do not see anything wrong with the information that has been given to consider as an addition to the price costing per page of an order. Since the writer works independently and works from a home set up, then yes, I too believe that the costing considerations cite provided are acceptable. If one were renting an office space, these factors would be worked into the client costing proposals, either in a specific listing or bundled into other service provisions.
What about the cost of running my air conditioner and the snack I had while writing
These considerations could also be worked in but not the cost of your cable bill and others. Yes, work everything in that relates to your on the job function.