Breath.......jokeNo. A sequence is gasoline engines, higher SAPS. B sequence are old diesel sequences. C is newer, Lower SAPS sequences (A3 and C3 are HTHS compatible, but differentiate in SAPS). E is commercial sequence.
A3 are more stringent sequence than A5. Castrol Edge 0W30, 0W40, Mobil1 0W40 etc. are A3, and you ain't gonna find A5 oils offering protection, especially for turbo engines like those oils.