Ok, but why spend 8 times the price of a chip when you can buy only one and use all its capacity?
You are confused as to the purpose of the A0 - A2 inputs.
Changing the I2C address of a 24xx256 (or 24xx512) does not give you access to any more memory. The 3 bits of the address determined by A0 - A2 simply determines the I2C address of that device and allows you to use multiple devices on a single I2C bus. A0 - A2 have nothing to do with the memory being addressed internally.
If you think you are getting 8x the storage, I highly recommend that you run some tests that write unique values to those “8” devices and see how much of it you can read back.
In the case of the 24xx1025 series, the 16 bit address in the protocol is insufficient to address the 128kbytes on the device, so they use two different I2C addresses to address the device. 2 bits of the I2C address are determined by A0 and A1 just like the smaller devices in the series; the other bit of the I2C is used as a “bank select”. Because of this, you can only use 4 of the 24xx1025 devices on one bus (software-wise, it’s exactly the same using four 24xx1025 or eight 24xx512).
Does changing the address on the EEPROM give you access to more memory?