It really doesn't matter. All of the advice is the same the consequences are the only things that differ.

Using the substitution method is easier for a job because a lot of them are not monitored. For probation it is and it is harder to do and you can get in a lot of trouble for getting caught.

If you use the dilution method and do it correctly you won't be in any trouble for a job or for probation.

If you mess up the dilution method you will potentially get retested for your job. If you mess up the dilution method on probation you violate and get in a lot of trouble.

The end.