the door header has to be level for the door to operarte correctly, the finish carpenter who installed the trim did it correctly keeping it tight. the mistake was by who ever built the bulkhead thats whats causing the trim to have to be cut on a taper to keep the reveal on the jamb even then still hard up to the ceiling.
in order to fix it the trim will have to be removed and the bulkhead fixed. if this is an older home and the contractor was working on time restraints or a budget id let it go, sometimes this situation is best to have kept out of level as the existing ceiling may be so badly out of level that by making it level it will drop the bulkhead down so much that it makes the trim so small it will look worse that what was done, its a question of how far to go with certain things. small details that arent structural, mechanical or involve water proofing sometimes have to be let go in order to keep a job moving along. belive me when i say this ive run into so many situations like this its not even funny, on some jobs everything has to be deadly level and plumb which can add days to a project making old look new but that adds thousands of dollars onto a project both in labour and material, not everyone wants to be paying through their teeth. some can afford it and demand perfection others just want to keep the budget in check
as for the trim package. the reveal of the header where it hangs past the side casings is far too much.. on a detail such as this 1/4"- 1/2" is the most appealing look.. otherwise it doesnt look balanced