Field Mapping from customers module to a custom module

@lucid
At second about save the record in the ‘Customers’.
You should make the file logic_hook.php in
custom/modules/Customers/
If I correctly understand your the file logic_hook.php in
custom/modules/
and it work for all modules.
The code of your function ‘copy’ should be another:

class PhoneGrab{
    function copy(&$bean, $event, $arguments){
        $moves_beans=$bean->get_linked_beans('accounts_moves_moves_1', 'Moves_Moves');
        foreach ($moves_beans as $moves_bean) {
            $moves_bean->customerphone_c = $bean->customerphone_c;
            $moves_bean->save();
        }
    }
}