People who value service feel most loved when someone helps them out. Particularly when that help is most needed. For these people, acts of service are not just an expression of love in the moment but a sign of longer term commitment and support, and a reminder that that person will be there for them in the future. As such, someone who appreciates acts of service will particularly question the love of someone who fails them in a time of need, break their commitments, or creates unnecessary work for them.
High scorers are likely to show their love through service as well. They are the type to clean someone's place without even asking. While this can certainly be appreciated by the right person, it can feel excessive to low scorers, who might view unsolicited acts of service as imposing or overbearing. In these circumstances, it is important to first establish rapport in the relationship before your acts of service will be truly appreciated.