Some funny results editting my patch (1.9.6)

I start off with my patch:

ch   address   type

1   1-12             Colorblock

2   13-24                 "

3   25-36                "

4   37-48                 "

etc etc

I want to change them all to 1 channel dimmers.

I type

[1][thu][15](type)(dimmer)

[select last][@]1[enter]

I end up with:

ch   address   type

1     1                  dimmer

2     2                 dimmer

3p1 25              dimmer

3p2 3                dimmer

4p1 37             dimmer

4p2 4                dimmer

5p1 49              dimmer

5p2 5               dimmer

etc etc etc

So what did I do wrong?

Thanks