Yes, he told Engels that in reference to some military maneuvers he suggested the English take, when he was writing as a war correspondent.[1] Not his economic works.
Please, do yourself a favor: stop digging. The hole is only getting deeper.
If you seriously believe that remark described a rhetorical strategy that Marx only used in that one particular context, I think you are the one who needs to stop digging. But obviously we're not going to come to agreement, so I'll bow out at this point.