@Phil9 , generally I would have used the heading foreign / employer paid housing/ living assistance-- this of course adds to your total foreign earned income ( eligible for exclusion , if ...). But in your case because you , as self-employed , would be filing a Schedule-C, your total gross income from the consultancy ( country B or otherwise ) would include total amounts paid by the client. Your expenses would include any travel, temporary housing etc. Note that per diem allowance varies by country ( and you generally have to subtract what it would have cost you had you eaten at home -- so I do not like perdiem. I would much rather show hotel / housing bills as expenses and forget about meals. Your total FEI exclusion max does not change, no matter what.
What countries are concerned? Assuming that you are US citizen. When did you leave USA i.e. do you qualify for the Physical Presence Test for 2019 ? Are you being taxed on the total world income ( foreign portion including country A and B ) by your resident country ?
