After using oil in an engine for a while, carbon builds up that helps seal the piston rings against the cylinder wall. When you change oils, the new oil might use a stronger/different detergent package. What one oil’s detergent package might allow to build up, another detergent sees as dirt and cleans it up disrupting the rings from sealing completely in the process. This is a worst case scenario but it does happen, and when it does you might experience an increase in oil consumption for an oil change or two until the engine 'gets used to' the new oil. We saw this happen a few times as the CI-4 Plus heavy duty engines oils were replaced with the CJ-4 oils. The older CI-4 Plus oils had a higher ash content which could build up in an engine over time. When the lower ash CJ-4 oil was introduced a 'clean up' operation started and disrupted the established carbon distribution in the ring lands and caused some engines to consume more oil than was normal for a couple oil changes. If an engine is in good shape and is holding it's oil with one brand of oil, it should stabilize pretty quickly if switched to an other oil. If on the other hand an engine is worn and using oil with one brand it is likely to continue consuming oil with a different oil.