No, he admitted to have done that in the past.
The motivation behind Götze was somewhat different, given Pep's interest in Neymar.
Also activating a 37 mio. contract clause is not exactly "weakening the opponent", especially with the BVB's track record of buying up talent at modest prices.
Also in case of Lewandowski it is NOT a matter of financial imbalances, since Real Madrid repeatedly increased their offer over Bayern's (or so it is said). If Lewandowski was only after money, he would just join Real, but obviously he prefers Bayern nonetheless, thus the reason here is NOT the financial imbalance between Bayern and Dortmund, but rather the prospect to play as starter in the currently best team in the world and with probably the most popular manager on this planet.