Help with understanding a commercial lease for my business

I am a small business owner in San Antonio TX. I am getting ready to sign a 5 year lease for my business. This is new for me as I've rented out residential space, but never commercial space. 

The monthly rent includes all the expenses (i.e. utilities, etc). However, there is a 3% increase each year + we have to pay increase in operating expenses each year for our share of the building, which is 8.3%. We're also paying for rentable space not usable space. Operating expenses = common area maintenance, taxes & insurance. 

My question is: is it typical to pay a 3% increase AND the increased operating expenses? I've read some articles online that recommend asking for the 2 prior year's expenses & the next 2 years budget to get an estimate of what those may be. 

My concerns: it's an older building / class B. The current condition is not the best, but the landlords are slowly improving the building. I don't want to be on the hook for all the upgrades they chose to make.