To be sure, the time it takes to progress from Step 1 to 10 has no bearing on the grade and step in which an employee is hired at.
If your colleague was hired into GS-15 Step 1, then it would still take this person the same 18 years to progress up the ladder to Step 10, assuming no irregular increases in pay.
If coming from private industry, entry step is often negotiable; prior industry salary serves as basis, so it wouldn't surprise me if this person started at Step 10 (not that it matters after Step 5 based on Bay Area locality).
If your colleague was hired into GS-15 Step 1, then it would still take this person the same 18 years to progress up the ladder to Step 10, assuming no irregular increases in pay.
If coming from private industry, entry step is often negotiable; prior industry salary serves as basis, so it wouldn't surprise me if this person started at Step 10 (not that it matters after Step 5 based on Bay Area locality).
In any case, GS-15 is a management position.