Long time ago, my neighbour had a Volvo fitted with a high boost aftermarket turbo. Used GTX, and I could never convince him to idle down. Screwed a bearing assembly.
Work had a heap of Agip Sint 2000, which he bought for $10 per litre. Was supposedly not compatible with mineral, so he gave it a nominal flush, and ran that stuff, still didn't idle down. Didn't wreck turbo either.
He'd drain the Volvo, and put the used synthetic in his "beater" for extended drains, with the risk being borne by a Datsun 1200.
Another AGIP experience. The last power station that we commissioned in this state was built, then put into storage for 7 years (a proposed aluminium smelter fell through).
The mills on one unit were stored with Shell, and the other unit with AGIP (long - political - story). The hydraulics were run once a month for a day. THe oil heaters remained in service 24/7.
After 7 years, the Agip oil was almost solid and black. The shell still looked good.
Problem turned out to be too high a watt density on the heater, but one oil cooked, and the other didn't.
BTW, we had another Agip affiliated contractor on site who called the logo "the dog with two d*&ks".