My modest experience in office (15 years ago) was usually original leases to new tenants ran 10 years but with an adjustment after the first 5 years then renewals usually for 5 year terms but some were for 10. At some point all leases come up for renewal. So were the 3.8 terms left originally a 5 year or 10 year terms?
Also what are the details of the leases. The office leases I dealt with covered rent of the space and on top of that rent tenants paid maintenance/repairs, utilities, parking and management fees.
The extra items were estimated at the beginning of each year, invoices created that included the extra items and the lease rent amount per month for one year. At year end tenants are invoiced IF they owed over the amount budgeted 12 months earlier, based on audited financials.
So if operating/maintenance costs go up it is a charge back to the tenants, over and above their agreement to pay rent for the space.