Hi Deb,
The Surface Go and Surface Laptop have different power supply requirements. The Surface Laptop for instance uses 15 volts 2.58 amps= 39 watts on the actual charger. The Surface Go on the other hand uses 15 volts 1.6 amps= 24 watts. You may try to use the PSU or charger of the Surface Laptop with the Surface Go however, you might observe that the device may charge faster. On the other hand, if you use the charger of the Surface Go with your Surface Laptop, you may observe slowness of charging. It is for this specific reason that Microsoft only recommends that you use the PSU that came with your unit when you purchased it to avoid any possible issues with battery charging. You may refer to the links below to see the power supply units for the said devices.
If you have additional questions, please let me know by replying to this thread. This way, I'll get notified and respond back to you as soon as I can.
Regards.