Performing two tasks simultaneously requires the coordination of their processing, especially in dual-task contexts with varying task orders. When task-order changes across trials, coordination demands result in performance impairments on trials with order switches relative to trials with order repetitions (i.e., order-switch costs), reflecting task-order representations maintained in working memory. Previous research has further shown that task-order coordination adjusts to prior experience with task-order switches versus task-order repetitions. Order switch costs in current trials (N) were reduced when the preceding trial (N-1) involved a task-order switch relative to task-order repetition. However, evidence for the assumed involvement of working memory resources in such sequential adjustment remains inconclusive. The present study investigates how working memory contributes to task-order coordination and adjustment by combining dual tasks with varying task orders and manipulating load through an additional working memory task. In detail, participants performed a visual-auditory dual-task paradigm involving letter and tone discrimination. Working memory load was varied via an additional updating task: Under high-load conditions, participants were required to maintain a number in working memory while continuously performing an arithmetic operation. Under low-load conditions, the same arithmetic operators were presented as fixation marks, without requiring the execution of an actual calculation. The results are interpreted and discussed in the context of current research on task-order coordination, coordination adjustment, and working memory.