What are both teachers referring to?

No, this parameter indicates the speed of lubrication pumping from the moment after the beginning. It also shows how fast oil is in engine work units. In this case, this parameter also indicates the number of power required for a rechargeable battery that is used in an engine beginning to the operating state (in this case, to a temperature of 40°C).

The second number commonly referred to after W (parameters are sometimes separated by dash, which is true, sometimes not), corresponds to summer or is also called high temperature mode for engine operation. This oil viscosity class displays its main characteristics in engine temperature in case of action - in the heating range of about 100°C.  5w30 engine oil

25W-50 Engine Oil - Quantum Lubricants

Its a High Performance Diesel Engine Oil. 

Quantum Lubricants - Best Leading Brand in KSA