ASUS TUF A16 - Charging wattage fluctuates a lot + Smart Charging sometimes stops at 79%

1- Charging wattage fluctuates a lot. While charging (for example at 30–60% battery), HWiNFO shows the charge rate constantly changing, for example: 95W 45W 70W 40W back up again This happens even when the laptop is idle and all background apps are closed. Is this normal behavior on ASUS laptops?

2- Smart Charging / Battery Health Charging issue. When Battery Health Charging (80% limit) is enabled, the battery sometimes stops at 79% instead of reaching 80%. The charging icon is still shown, but it stays at 79% until I unplug and reconnect the charger. This doesn't happen every time, and when I disable Battery Health Charging, the laptop charges to 100% normally.

3. Full Charge Capacity

My battery report shows:

Design Capacity: 90,005 mWh

Full Charge Capacity: ~88,300–88,600 mWh

Wear Level: around 1.9%

Cycle Count: 0

I noticed that another ASUS TUF A16 owned by my friend has a Full Charge Capacity of about 91,500 mWh (higher than the design capacity) and shows 0% wear.

Is it normal for a brand-new battery to have a Full Charge Capacity lower than the Design Capacity, or should I be concerned?

Has anyone with the same model experienced any of these issues?

Thanks!