Update your settings

Good day everyone. I am currently on learning phase to use WinCC Unified on TIA Portal V18.
I am facing an issue with setting up the Performance Bar/Pie Chart and I am unsure what else I should try to resolve it. I was inspired by a video from the MR Automation 247 channel and would like to seek guidance from all of you. [Below] is the reference video.
Installed Softwares
1) Totally Integrated Automation Portal: Version V18 Update 4
2) SINAMICS Startdrive Advanced : Version V18 SP2
3) STEP 7 Professional: Version V18 Update 4
STEP 7 Safety
4) WinCC Advanced / Unified PC Version V18 Update 4
WinCC Unified Calendar Version V18 Update 1
WinCC Unified Performance Insight Version V18 Update 1
Issue Description:
I can correctly display the performance percentage using an IO Field by implementing a script that calculates the performance based on PLC tag values. However, when I try to display the same value using a Performance Bar or Pie Chart, I used a KPI formula with operands that reference the same source tags. Unfortunately, the result is incorrect.
Both the IO Field and KPI Counter operands reference the same PLC tags, but the results are different. The IO Field gives the correct value, while the KPI formula does not.
I must have missed some important steps or misconfigured some settings. I would appreciate any guidance on troubleshooting or best practices to resolve this issue.
Thank you in advance for your help!