JEDEC standard spec JESD3-C provides all the information you need to know about JEDEC files and how to read them.
L00064 is address 08h, so the bits following "L00064" in the JEDEC file start at 08h and go to 15h. The Lxxxxx fields in the JEDEC file indicate the "bit-rank" in the data stream. To find out what address of the byte pointed to by a given L-field, you divide the xxxxx in the Lxxxxx field by 8. For L00064, the following 8 bits belong to address 64/8=8.