You made a math error: You can encode about 300 addresses, at 36+8 = 44 bits per item, not 45 addresses, at 36*8 = 288 bits per address. The bits are additive

You made a math error: You can encode about 300 addresses, at 36+8 = 44 bits per item, not 45 addresses, at 36*8 = 288 bits per address. The bits are additive, because we're storing an address and data, not a byte of data per bit of address.