Clause in a Sentence

[Brahman]

"Yesterday afternoon, I had left my pair of Nike suede shoes, as I always do, outside my house."

I have three questions concerning the above sentence:

1. What is the technical term for the expression --- "as I always do"? (Is it called a phrase or clause?)

2. Has that expression, i.e., "as I always do", been put in the right place in the sentence?

3. Would it make any difference to the meaning if it is anywhere else like in the following cases?

a. "Yesterday afternoon, I had, as I always do, left my pair of Nike suede shoes outside my house."

b. "Yesterday afternoon, I had left, as I always do, my pair of Nike suede shoes outside my house."

[nevertheless]

Yesterday afternoon, I had left my pair of Nike suede shoes outside my house, as i always do.
It is a phrase just like "as usual".
As you can see it wasn't put in the right place, i got it corrected.Pay attention to the number of commas.
No it wouldn't, but it wound sound inappropriate.(IMO)