Supply chain digitalisation equipment’s raise concerns for hospital decision-makers, especially regarding the cost-efficiency ratio, usually evaluated through health technologies assessments (HTA) at a national level or by return on investment (ROI) calculations by the hospital finance department. Unfortunately, none of the two methods identifies organisational impacts, nor hidden gains and costs, especially those that are related to the internal reallocation of resources as shows the example of automated dispensing systems (ADS) in the central pharmacy of a French hospital with a posteriori analysis from the hospital perspective. The introduction of the ADS caused some hidden costs or gains, which do not generate any financial flow and which are therefore not valued. When they are valued, as we do in this study by including them in the ROI calculation, the results change dramatically: the profitability of the investment goes from negative to positive. Given the importance of hidden gains and costs related to organisational impacts, they should be included in evaluations.