The difficulty of viewing photos outside, because the official fees (national income) are the same, the difference is the fees charged by the agency. If the equipment is relatively large, it is necessary to draw a three-dimensional diagram or an effect diagram, so the cost is high. If you just take a little ps after taking pictures, the cost is lower.
They are all official expenses of the Patent Office, including application fee, registration fee, annual fee for the first year and stamp duty on certificates. If an agency is entrusted, the agency fees charged by the agency will be different.