Final answer:
Machine-made wigs are difficult to restyle because the direction of the hair is fixed by the wefts sewn onto the cap, making any change in hair direction challenging.
Step-by-step explanation:
It is difficult to perform a design service on machine-made wigs because the direction of the hair is determined by the position the weft is sewn to the cap. Unlike hand-tied or lace front wigs, machine-made wigs have wefts of hair that are sewn into the cap in a fixed direction, which makes restyling into a different direction challenging. The cap construction of machine-made wigs does not allow for the same flexibility in styling as seen with other wig types where individual hairs can be moved more freely.