Should the sales managers focus more on the amount they sell or the profit they gain? if there is a conflict between the two,what would you choose?

I would opt for Sales Revenue in this case as long as the over all average margin is profitable.

Sales and profits are interrelated, New business usuually focus on high sales with low margin to penetrate in the market. However good Sales manager should focus on both sales and profits by setting target of amount of profits to be achieved at the end of the month / quarter for that they can plan to sell high volume with low margin and low volume with high margin. A business is known to have made a profit when its revenues exceed its expenses and a loss when its expenses exceed its revenue. 

Sales Manager should make a sales plan as a strategic document that outlines the business targets, resources and sales activities. It typically follows the lead of the marketing plan , Strategic palnning and the business plan with more specific detail on how the objectives can be achieved through the actual sale of products and services.

Sales management is a business discipline which is focused on the practical application of sales techniques and the management of a firm's sales operation. It is an important business function as net sales through the sale of products and services and resulting profit drive most commercial business..