Can implant exchange increase capsular contracture risk?

I would think carefully about replacement of your implants.  It is possible that you could develop capsular contracture in spite of your good result the first time.  In addition, all the other risks of surgery are inherited.

Exchange of implants is most easily performed in the same plane.  I would recommend maintaining the same implant pocket and repositioning under the muscle if there is significant risk of capsular contracture.  There are no immediate reasons for you to replace the position to subpectoral. 

If you have had success with your current implants in the subglandular position, then you should be fine to have them removed and replaced in the same position. However, if you have had problems with implants in the subglandular position (i.e. visible or palpable rippling, capsular contracture, unnatural appearance) then having them moved to the sub-muscular position is a good choice. Implants in the subglandular position do have a higher risk of developing capsular contracture in general. This is one of the reasons that I generally recommend placing implants below the muscle. But if you have done well with your implants in this position, then I would leave them there.