It sounds as if it may have just gulped some oil into its breather for some reason (such as the engine being tilted at some point, and/or the sump was over-filled with oil) and has cleared itself. That does not explain the original shut-down though, unless it was due to low oil as you thought. So, perhaps the oil got low, the engine shut down, something happened during the service that got oil into the breather hose, it's now gone, and all is well. It would be good to know how the oil got into the wrong place, though, so we could be sure that's all it was.
I have seen reports that Intek engines are prone to producing heavy white smoke if they are run on a cross-slope, left side down-hill. However one of the accompanying explanations of why this allegedly happens (blown head gasket) is not sufficiently detailed to convince me. A blown head gasket could certainly cause the problem, if it was blown between the combustion chamber and the pushrod compartment running into the crankcase. However this would only happen on a new engine like yours if the engine design was poor (as claimed in the report) or the cylinder head was badly installed. Here is that report:
http://www.fixya.com/support/t1910391-14_5hp_b_s_ohv_looses_powes_blowsHere is a miscellaneous set of reports, some of which make sense to me and may be relevant:
http://www.fixya.com/support/t2674300-see_lot_white_smoke_out_outletThe number of reports of this problem with Intek engines is a bit of a worry - it may be something the engine is prone to. There are three themes in the explanations:
1. Mower was running on a cross-slope when the smoke happened. In this case you just have to watch and learn what your mower is capable of. Remember, Briggs and Stratton specify that you do not run the engine on any more than a 15 degree slope.
2. Mower was over-filled with oil when it happened. Note this could be due either to putting too much oil in the sump, or the carburetor flooding and petrol passing through the main jet into the intake port, past the valve, past the piston rings, and into the sump, so there is petrol in the oil, and the oil level has a tendency to rise, not fall, with time. If this happens you need to fix the flooding carburetor, and probably also make a habit of turning off the fuel when you park the mower. Rising oil level with an air-cooled engine that has gravity fuel feed, always means fuel or water is getting into the sump. It needs to be fixed immediately, and the oil changed.
3. Mower had a mechanical malfunction causing high crankcase pressure when the smoking happened. In this case, the problem will be recurrent. The breather tube will contain oil if you stop it while it is still smoking - in fact in a severe case the tube may blow off due to the internal pressure. Case three is the one I posted about earlier in this thread; if the rings are broken or worn out, or the head gasket is blown into the push rod space, blow-by will cause high crankcase pressure, and high crankcase pressure will blow oil into the breather system.
