can someone help me with some query?

1) for power prepaid, if i load rm30 then it's effective for 30 days. how about i reload another rm30 on day 20...will the active period be extended from day 20? or added to the initial 30 days?

2) can i reload at one go rm100 (or even more) so that active day goes to day 100.

3) if i buy the internet data booster addon, (the one where rm3 last for 3 days)...does the addon auto renews or do i have to manually purchase every time?

thanks for any help!