Goal Alignment among Physicians

An elderly physician has built up his own practice into a quite valuable business. Now that he is thinking of retiring, he wants to take on a partner to learn the business and eventually buy the practice in three years. Her compensation will be a salary plus $25\%$ of the profits if they are below the historical average and $50\%$ for any increase above the historical average. The eventual purchase price for the practice will be $5$ times the average profits over the three years. Discuss the efficiency aspects of such a contract. Are the incentives of the buyer and seller aligned?