The footnote to Matthew 26:13 says "She is probably not the harlot of Luke 7, but Mary, the sister of Martha", and the same incident is described in Mark 14:3. The footnote indicates some slight possibility that it might be Mary. There is a big difference in the timing of the acts (one during the passion week and the other during the ministry). Even though the harlot's annointing was done a long time before the events of the passion week, is it highlighted during the Bridegroom services because she was an obviously sinful woman, as opposed to Mary the sister of Lazarus?
Sorry to seem like such a simpleton, but I'm no biblical scholar for sure.
It's actually a common Orthodox practice to superimpose two different stories if (a) they're similar, and (b) they both relate to a particular theme - in this case the anointing of Christ's feet (i.e. the act of humility, repentance, glorification, and preparation). One of the gospel readings used on feasts of the Theotokos is the account of Martha and Mary working and listening (respectively) when Jesus visits - the Mary being spoken of isn't the Theotokos, but the Fathers were making a point that the Theotokos was herself a Mary who listened attentively to the teachings of her Son, which is another reason why she's blessed; and when the gospel cuts out a big chunk of the story and moves on to the women who cries out "blessed are you and the breast that nursed you," Jesus' response of "blessed rather are they who hear the Word of God and keep it" doesn't exclude Mary, but rather gives her glory because she indeed heard and kept that word.
Also, cutting and pasting together two gospels is done all the time between Holy Thurs and Sat, and even on other feasts (the two different gospel readings used for feasts of the Theotokos come to mind; one makes a small cut {Mary and Elizabeth}, the other a big one{Jesus with Martha and Mary}).
