The main variables are legal preparation and how much corporate evidence must be rebuilt. A current blanket approval removes repeated structural work, while the individual route requires it for each case. Credential assessment may be an added item where the blanket category's professional element is in play.
Price the fallback, not just the plan
The costly outcome is discovering late that the employee does not fit the route chosen, and then preparing a second case under time pressure. Ask counsel what a switch would involve and cost before committing, so the comparison reflects risk rather than only the smoother path. Government charges differ between the routes and should be confirmed at the relevant step rather than estimated now.
Add one item ahead of the route comparison: a short check of the person's own history, priced separately. Time already spent in L classification, a period on another group entity's payroll, a secondment onto a customer's books, or a stretch as a contractor can each change what is available regardless of which route is more convenient for the employer. That answer costs little and determines whether the route question is worth debating at all.
Hypothetical example: a cleanroom qualification specialist's employer spends three weeks comparing the two routes in detail, and the subsequent history check establishes that prior time in classification limits the position substantially, which would have reframed the entire discussion had it been done first.