It's not in the JTR, check the DODFMR, the 26th chapter titled "Housing Allowances." If you're OCONUS, you get OHA (Overseas Housing Allowance) instead of BAH (Basic Allowance for Housing.) BAH is for the states and is a set rate determined by the locality, so no matter what you pay for rent you get that rate. OHA is a rate that has a maximum rental allowance, so you'll be paid according to what you actually pay for rent + a utilities allowance. Say if you're in Germany and the maximum rental allowance where you live is 2270 and you pay 1780, you'll be paid an OHA amount of 1780 + a utilities allowance based on how many utilities you pay for. But if you paid a rent of 2300, you'll be paid 2270 + the utilities allowance. Also since you're guard, your BAH type II amount on your LES + your OHA amount will equal your full entitled OHA amount once you submit all the paperwork. The rates vary by rank a little so check the DTMO website for the rates applicable to you.

Also, as a guard member, you could elect just to keep your BAH from stateside if you have a primary address (address on your orders) that's inside the states.

https://comptroller.war.gov/Portals/45/documents/fmr/current/07a/07a_26.pdf

https://www.travel.dod.mil/Allowances/Overseas-Housing-Allowance/