So a word of advice. When you cut the bands on 25' of flashing and it starts to unroll and head for the edge at a sprinters pace, try not to grab it to pull it backwards.
I deserve every single one of those royalty checks. Being a child actor is tough work. You try working with Tim Allen. He made me cry over a dozen times.
I decided to first put down a layer of Blackjack and then flashing and then another layer of Blackjack to solve my leak.
Old houses, nice when they work, hate them when they break.
This is a good short term solution IF you put a layer of plastic mesh in the top layer of mastic to hold the asphalt together. It will shrink and crack after exposure to UV.