A drone land surveying operator has provided the following description of their business operations:

"I run a local drone-based land surveying service. I charge clients based on the total area of land surveyed, not how many separate flight paths are required. If a client requests multi-spectral imaging instead of standard high-definition, I do not charge any extra because my drone already has both sensors mounted. I prefer to fly early in the morning because winds are generally calmer then. I need a software system to help me keep track of the remaining battery capacity of each drone model in my fleet. Luckily, every drone has a unique alphanumeric serial number, so it is very easy to identify them in the system. I charge £120 for every 50 hectares surveyed, and I always round this up to the next 50-hectare block (for example, a 65-hectare survey would be charged as two 50-hectare blocks, or £240)."

The software developer has decided that the following two points are the only important details from the client's request:

• The charge is based on the area surveyed, not the number of flight paths.
• The charge is £120 for every 50 hectares.

State two other relevant details that the developer has missed.