I will design electronics boards, pcb modules with microcontroller firmware n sensors

I have my main suppliers in China. But I have developed several circuit boards and products for customers elsewhere. I adapt to the client's work scheme, although my usual way of working consists of the following:

1. The customer pays for the product development work (feasibility study, planning, design, component selection, management, etc.)

2. I develop electrical diagram, printed circuit and Firmware (if needed). 4 deliveries, the client pays 20% of the total cost as quoted in the planning phase each time

3. In the last stage, the client gets the prototypes, approves and I deliver all the documentation necessary for manufacturing. The customer can have their product manufactured on their own. Diagrams, parts lists, PCB design and HEX files for the MCU are delivered

4. If customer decides to manufacture with me, I offer a discount of up to 20% of the production cost or up to 60% of the amount paid for development. Because I'm interested in maintaining the relationship as the main product supplier in subsequent product orders.