May I humbly suggest that you stay away from Telesteps?
This particular brand was the ladder of choice as per management of a very large carrier that I used to work for.
I fell, another adjuster fell and suffered a severe injury to his arm (let alone his dignity) when we were in New Mexico. I have returned two ladders for repair and the replacements were just as bad as the originals.
I have used a generic copy of Little Giant in the 17 ft version and found it to be very safe and predictable.