hi. yes. this problem i have. you are not able to deliver real value, because odoo will override FIFO, lefo etc.

but what i allready have solved, there are 2 modules, which is oca and helps in this case. so you need to install these modules. they will allow, you easy reserve and deliver (will be standard odoo valution fifo/lifo) or you are able 'unreserve' in delivery and select exact lot. valuation will be correct.
'lot tracked fifo valution' and this one  https://github.com/OCA/stock-logistics-warehouse/tree/12.0/stock_quant_manual_assign