Using the function Get Absence In Days For Period Based On Calendar Days For Time Types() includes both approved leave requests and pending leave requests.
Employee Central - Time-Off
This is expected behaviour - Time Account balances for pending requests are also included in the function Get Absence In Days For Period Based On Calendar Days For Time Types()
If you would like to have this feature introduced, you can submit an enhancement request in Idea Exchange which may be considered as a future enhancement and let the community know that you are one of the accounts that is requesting this kind of functionality.
Please see the below KBA for more information.
2090228 - How to submit enhancement requests for SAP SuccessFactors products
Get Absence In Days For Period Based On Calendar Days For Time Types(), function, pending absence, pending leave request, approved leave request , KBA , LOD-SF-EC-TIM , Time Off , Problem