Home Office Deduction

I have a dedicated space at home that I use for my business.  I've read that there is a $5 per 300sf (max) 2022 deduction.  Is that for the entire deduction, or is that a per month deduction?  If I've used my place every month for business, shouldn't I be able to use the deduction monthly? $1500 x 12?

 

I've also read that there is alternate option to use 25% deduction that can be used.  Is that 25% of each monthly rent/mortgage payment?