That sentence is incorrect. The closest correct form would be, "The person shall perform their services expeditiously, as is consistent with such skill." One could also say, "The person shall perform their services as expeditiously as would be expected from such skill" or something like that.
PS: The use of the word "person" is unnatural here; I can understand why you would use it here, but I would like to make sure that you know that one would say "he/she/they" or specify the person's name or role.
[Not a teacher]