wait till u have to repairs and maintenance.

Yes.  That will be in year 20. For battery replacement. Coz first 10 years will be battery free. Year 11 maybe u opt for battery solution. And let’s say battery warranty is 10 years and it kaput in year 10, ngam ngam free battery replacement.  So another 10 more years. Total 30 years no need to worry about battery.

Actually there is no battery in the setup. Coz it’s under NEM.  TNB will work as the battery for free.  So there is no battery to replace.

Do you know the NEM only valid for 10 years? Your "return" has an expiry date. Year 1-5 trying to recover, then Year 6-10 you earn some. Year 11 onwards, you are on your own.

Since many have experience with solar here, i would like to ask.

i've heard some feedback from few different solar provider/installer on their home. Feedback received is the power generated from solar, differs from the power received in TNB based on the power written on the electricity bills. Is this normal?

Example: Generate 600kWh seen in the app, but in TNB bill only show received 300-400kWh?

But as far as i know, there isn't any battery pack and the system flow, suppose, whatever generated, will flow to TNB, then electric source come direct from TNB? What they said is, this flow, even if power outage from TNB, even your house have solar, also will be affected immediately.
I've yet to install, just feedback from existing users, from different provider. It is the reading from the app by the provider.