advance auto parts , inc . and subsidiaries notes to the consolidated financial statements december 31 , 2016 , january 2 , 2016 and january 3 , 2015 ( in thousands , except per share data ) 2 . inventories , net : merchandise inventory the company used the lifo method of accounting for approximately 89% ( 89 % ) of inventories at both december 31 , 2016 and january 2 , 2016 . under lifo , the company 2019s cost of sales reflects the costs of the most recently purchased inventories , while the inventory carrying balance represents the costs for inventories purchased in 2016 and prior years . as a result of utilizing lifo , the company recorded a reduction to cost of sales of $ 40711 and $ 42295 in 2016 and 2015 , respectively , and an increase to cost of sales of $ 8930 in 2014 . historically , the company 2019s overall costs to acquire inventory for the same or similar products have generally decreased as the company has been able to leverage its continued growth and execution of merchandise strategies . the increase in cost of sales for 2014 was the result of an increase in supply chain costs . product cores the remaining inventories are comprised of product cores , the non-consumable portion of certain parts and batteries and the inventory of certain subsidiaries , which are valued under the first-in , first-out ( 201cfifo 201d ) method . product cores are included as part of the company 2019s merchandise costs and are either passed on to the customer or returned to the vendor . because product cores are not subject to frequent cost changes like the company 2019s other merchandise inventory , there is no material difference when applying either the lifo or fifo valuation method . inventory overhead costs purchasing and warehousing costs included in inventory as of december 31 , 2016 and january 2 , 2016 , were $ 395240 and $ 359829 , respectively . inventory balance and inventory reserves inventory balances at the end of 2016 and 2015 were as follows : december 31 , january 2 .
how the cash flow from operations affected by the increase in inventories at lifo net in 2016?
inventory quantities are tracked through a perpetual inventory system . the company completes physical inventories and other targeted inventory counts in its store locations to ensure the accuracy of the perpetual inventory quantities of merchandise and core inventory . in its distribution centers and branches , the company uses a cycle counting program to ensure the accuracy of the perpetual inventory quantities of merchandise and product core inventory . reserves for estimated shrink are established based on the results of physical inventories conducted by the company and other targeted inventory counts in its stores , results from recent cycle counts in its distribution facilities and historical and current loss trends . the company also establishes reserves for potentially excess and obsolete inventories based on ( i ) current inventory levels , ( ii ) the historical analysis of product sales and ( iii ) current market conditions . the company has return rights with many of its vendors and the majority of excess inventory is returned to its vendors for full credit . in certain situations , the company establishes reserves when less than full credit is expected from a vendor or when liquidating product will result in retail prices below recorded costs. .