The suite shown about is about Yen20,000 / night. However, they have smaller flat at about Yen 10,000 - Yen14,000.
However, they don't have listed price in their web-site and the prices quoted about are for low season. If you are going on other seasons, the price may be altered.
If you would like to check in this service apartment, I suggest you contact their Lize. She is a Japanese from Australia speaking English. You may mention to her being referred by my wife Doris. This hotel is looking for tie-in business from CX. I hope she will grante you special discount.