Zitacuaro or Morelia and senior discounts

I am trying to make a bus reservation and use the senior discount that a Inapam card authorizes. The web sites for two bus companies I looked at did not seem to allow getting the discount. Is it necessary to go in person to get the senior discount?

Separately I am looking for suggestions for a guide from either Morelia or Zitacuaro for a butterfly trip mid January.

I do not want a guide from Zihua. Gracias