Change commerce price I've setup another commerce price field which I want to use instead of 'default' commerce_price field (under certain conditions). hook_commerce_product_calculate_sell_price_line_item_alter() does the job on full product page but it doesn't work 'globally'. In shopping cart / order page   price goes back to default commerce_price field. Actually it's acting strange because when I add product to the shopping cart it shows amended price but it goes back to default price once page is refreshed...

p.s. I can't use Rules to change price.
Unfortunately using rules is the only option to dynamically alter a product's price in Commerce 1.x. From the 2.0 roadmap:


  In Commerce 2.x, we should ensure that our modules define robust internal APIs that are then used by forms, Rules actions, etc. as opposed to embedding functionality into these systems' related callbacks. Most notably, we should seek to make price manipulation and price component management much easier as we open up the sell price calculation process to direct manipulation in module code (as opposed to strictly using Rules) when sell price pre-calculation is disabled.


emphasis mine.