The representations made by PLEC on their website (which you certainly could access through archive.org indefinitely) are extremely vague, other than free re-treatment in the first year (but not before 6 months), and a "facility fee" (but no doctor fee) thereafter for life.
The real 'problem' arises if there were to be a disagreement between you and the Dr. as to the necessity of a re-treatment. Eligibility criteria is never discussed. The lack of negative online feedback indicates to me that refractive surgeons (PLEC being no exception) are fairly generous with their re-treatments if legitimately in the interest of the patient.
Its no problem to walk around with 0.5D or even 0.75D of astigmatism. Those levels will reduce final visual acuity. Could be the difference between 20/10 and 20/15, for instance.How does this level of astigmatism affect you? Do you need glasses to correct? I don't recall, how far out from surgery are you?