There is no universal cost winner between plates and dry ice. Use frequency, preparation, supply and product conditions to compare your actual trip records.
Define the same job
State route, load, delivery pattern and the product's accepted conditions. Do not compare costs from different jobs side by side.
Record each method's costs. For plates, collect purchase, freezing energy, labour, loss and cleaning costs; for dry ice, collect purchase, supply, waiting loss and handling costs from invoices and work records.
Verify operational suitability separately. Measure each method on a representative route; record product position, time, lid openings and site conditions. For dry ice, review the supplier safety data and workplace CO2 risk procedure.
Show the comparison per trip and for the selected accounting period, stating assumptions. If product conditions are not met, lower cost alone does not make a method suitable.
