I was reading somewhere (can't remember which post, I've read a lot in the past days) that if I book my flight with AC, in cabins below Y, but claim my points with LH’s M&M, then I would receive 100% points instead of their usual 25% (Economy Basic) because my flight was with an alliance member. Is this correct? If so, then it’s always better to book discounted flights with AC and then claim points on LH, right?

Thanks a lot!