Ok, then if it were me, I would do the following:
- Open a blank Pluma document (you can find Pluma in the "applications/accessories" menu)
Paste the following into it:
sleep 5
xinput --set-prop "USB Optical Mouse" "Device Accel Constant Deceleration" 4
xinput --set-prop "SynPS/2 Synaptics TouchPad" "Device Accel Constant Deceleration" 6
Save the document somewhere in your home folder as "mouse-set.sh"
- Open Caja and navigate to where you have the "mouse-set.sh" file stored and right-click it and select "properties" and then go to the "permissions" tab and check the "allow executing file as program" check-box . See below:
Then close the "properties" dialog box (congratulations, you have just written your first bash script.... 
)
- Go to "system/preferences/personal/startup applications" and click on the "add" button.
Put anything you want in the "name" field
Put anything you want on the "comment" field
For the "command" field, use the "browse" button to navigate to where you have stored your "mouse-set.sh" file and select it. When you have done all of that, it will look something like this:
Then click the "add" button to confirm. Then close the "startup applications" dialog.
- Log out and then back in.
That's it. You should now find that your mouse works as required automatically at login.