When can you extend your visa online?

This is what I've read, but it's a bit confusing.

1st extension (29-day visa waiver extension): can be done online (extends the initial 30-day visa-free entry to 59 days total).
2nd to 5th month extensions: must be done in person at a Bureau of Immigration (BI) office (note that an Alien Certificate of Registration, the ACR I-Card, is required from this stage).
6th month extension: can be done online.
7th to 12th month extensions: can be done online.
After 12 months: stays over one year no longer qualify for online extensions and must be handled entirely in person at a BI office.

If I'm understanding this correctly:

Arrive and do the 29-day extension online (already did this).

In person for a 60-day extension.

Online for a 60-day extension.

In person for a 60-day extension.

Online 60-day extension x2.

The rest must be done in person.

Is that right? Also, I assume that even if I extend past a year, if I leave at day 350 I can still get my ECC at the airport (it says under 1 year you can get it there).