The reason the BSRs of equal attacking stats are different is that BSRs are relative to the power levels of other Pokemon. Since there are more powerful physical mons than special mons, PS is depressed and SS is elevated. This is something I don't really agree with, since once you start considering other Pokemon, you really should be considering the metagame as well. The fact of the matter is that 90 base Atk hits just as hard as 90 base special attack. Still, I don't make the rules, so I post the BSRs anyways. Also, I'm not sure where you're getting the idea that, for example, your spread is closer to even offenses than mine. Your spread has PS and SS of 175 and 146, compared to my PS and SS of 136 and 141.