In order to write a macro you need to know exactly what you want to happen,
and I don't think you have provided sufficient information to understand exactly
what you enter or want created automatically. For instance adding two rows at
a time not a typical spreadsheet application, so possibly you provided the
wrong cell addresses and meant for the additions to be on the same row, but
in any case I don't have an idea of the order that you are entering information
and what is to be automated.

In other words B1 and B2 are NOT on the same row.

When you change the value in A1 can the new row(s) be created
automatically, or id the calculated value going to appear when you
add a new cell(s) below.

If you look over the page reference I provided earlier you would get
an idea of what you can do and help you provide a better definition
of what you want done.