Just because an agency charges a fee which covers or exceeds their costs doesn't mean they get to keep those fees. They may go to the government's general reven

Just because an agency charges a fee which covers or exceeds their costs doesn't mean they get to keep those fees. They may go to the government's general revenue fund or they may be used within the Home Office to fund other activities within the agency. Even if the fees are directly returned to the immigration agencies with the Home Office they still may not be authorized to hire additional staff without prior approval through the budgeting process. Most governments don't like to give agencies unfettered ability to increase agency staff. I have no idea what the situation is with the Home Office. They very well may have the required authority to increase staff but to assume they do doesn't seem logical since this is against the norm for government agencies.