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, Mobil 1 0W40 etc. are A3, and you ain't gonna find A5 oils offering protection, especially for turbo engines like those oils.