Is adjustable life insurance the same as term life insurance?

No. For the most part, any type of adjustable life insurance is usually some type of a permanent plan. Permanent Life Insurance has the cash buildup to provide the ability to purchase additional coverage, known as paid up additions.
The only thing that is usually flexible about term life insurance is that you can reduce the face amount if you do not feel that you need that much coverage.

There may be a very select few that give you an option to purchase more coverage down the line without underwriting, but they definitely are not the norm.