MOST motor bearings are greased with a high temperature non-EP polyurea grease with a base viscosity right around 95-100, NOT lithium based. So right off the top I'm suspicious that you're using the wrong grease system, not just an odd viscosity. The vast majority of motor manufacturers and motor rebuild shops as a consequence use Mobil Polyrex EM or Polyrex EM 3 and nothing else. Once in a while this gets them in trouble with the high pressure roller bearings where a high temperature lithium grease is appropriate but that's rare. Either way, lithium greases and polyurea greases are in general NOT compatible although the reality is that this prohibition references older lithium formulations which is no longer really an issue, but the stigma against mixing greases has lasted for decades.
The EP additive is specifically added when bearings experience high thrust loads (where a thrust bearing is not used). That's not the case for most motor applications...we avoid this condition like the plague. The EP additive seriously decreases grease life so motor applications specifically call for non-EP greases. However obviously if your motor is under high thrust loads, then you need the EP additive because the grease life is already seriously impacted so in that case you'd be going back in that direction. But the general motor industry tribal knowledge is to specifically avoid EP additives. In general it should be the rule with everyone else too for the exact same reasons as to whether or not to use an EP additive but its just that with motors it is the exception rather than the rule as far as its use.
Some large motors do use high pressure roller bearings though and that's where some manufacturers switch back to a high temperature lithium grease, which is where your choice comes in. But keep in mind that's the exception, not the rule. The Shell equivalent to what 90% of motors use (Mobil Polyrex EM) would be Shell Gadus S2 T100 2, but you will run into serious problems with warranty issues. Same problem comes up with certain compressor manufacturers that standardize on Mobil Rarus oils to the point where switching manufacturers runs afoul of warranty issues. And your Shell distributor should know this and have access to this information. Granted the fact is that Gadus S2 T100 2 SHOULD be a drop in replacement for Polyrex EM but since manufacturers give a very specific make/model for the grease in their warranties, you are normally highly limited in your choices. This is done for a reason...if the spec was opened up to just any polyurea non-EP grease, who knows what garbage will get put into a motor, not necessarily a reputable manufacturer like Shell.
I work for a motor shop so we have to abide by the industry rules whether or not alternatives might make sense for individual cases.