You can add the label by dual axis.
The main steps are,
1. Drag & Drop a second SUM([Number or Records]) to Rows
2. Drag & Drop SUM([Number or Records]) to its Label mark and modify Label settings (Alignment - Vertical - Top)
3. Check Dual Axis
4. Right-click the axis on the right, and select "Move marks to back"
Worked perfectly!. Thank you