I don't think all the hair grows together. if so, then everyone would be bald for some time before the hair started growing back. If they don't grow simultaneously, then some hair will grow back to full size (if it was cut right in the start of the anagen phase) and some other hair will grow back to half or less the full size (if it was cut on half of the anagen phase or later), and maybe you just don't notice it.
I don't think all the hair
I don't think all the hair grows together. if so, then everyone would be bald for some time before the hair started growing back. If they don't grow simultaneously, then some hair will grow back to full size (if it was cut right in the start of the anagen phase) and some other hair will grow back to half or less the full size (if it was cut on half of the anagen phase or later), and maybe you just don't notice it.