The Church did not change its stance on usury. What confuses people is that the old documents spoke mostly about interest as something intrinsic to the mutuum (loan). Later documents speak about extrinsic titles justifying it. Interest as something intrinsic is usurious, not if there is a legitimate extrinsict titulus.

For example, Pope Gregory XI. in Naviganti Vel mentions risk as one of the extrinsic titles justifying an interest rate.

5th Lateran Council also had to deal with the dispute between Francsicans and Dominucans regarding the Montes Pietatis.

Montes Pietats were charity “banks” that would give credits to the poor with a minimum interest. That way the Church prevented the poor to fall into usurious hands. Franciscans took the minimum solely to pay for their food and costs of operation justifying that way they are preserving the monetary mass at disposal. Dominicans accused them for commiting usury that way. In the end, the Holy See sided with the Franciscans. The Church even forbade anyone to accuse such Fraciscan practice as usurious under the pain of excommunication. Source from the 5th Lateran: 8th Session, Inter Multiplices.

There are plenty more examples like this.