TA issue

in the middle of week, my boss has offered our student to take up the extra TA and he'll pay her the air fare for 2 conferences. which means, his account can stop bleeding for $12K for this year. (TA job gives 6K + department top-up 6K).
if the department is going to open an operational fund account for each deficit prof, y can't keep taking the RA $$ from there?
well.. i m not an accountant nor mathematician. but i think u can tell the difference then...
my friend doesn't know whether she should take it or not.
if she's not, seems like she's causing a trouble n she's afraid of a bad reference letter in the future.
if she's taking it, i think not just her, but the whole group is affected as we r gonna share some group jobs for her.
she just doesn't understand y the affected portion is the students. but not the profs?
finally, it's solved. my boss can pay her RA through that opeartional fund account n so she can keep on taking 2 TA units. no more.