我们几个朋友今年租了一个新加坡的condo。按照合同我们需要每三个月做一次空调维护。在我们入住第三个月的时候我们做了一次general servicing，这个时候检查出来空调有几台已经堵了，有一台需要加gas。 房东让我们负责做chemical overhaul和加gas，如果某一台空调的费用超过200块，那我们租客付200，超过的那部分房东付。我们咨询了清洗空调的公司，做chemical overhaul和加gas总共需要700多块。我们觉得这样对我们不公平， 因为每一台空调的费用都是100来块，意味着房东可以一分钱不掏。我们觉得被房东讹钱了，毕竟我们才入住三个月，空调就有这么多问题。但房东说我们入住期间就该我们租客负责。小弟想求助一下大家这种情况是我们租客的责任吗，有没有什么建议，感谢大家

这里是我们合同的一部分，我觉得我们已经按照合同在做定期维护，再让我们花大价钱清洗有点过分了：

MAINTENANCE OF AIRCON： To keep the air-conditioning units installed at and for the said premises in good and tenantable repair and condition which air-conditioning units are to be serviced and maintained at least once every three (3) months at the expense of the Tenant by a licensed air-conditioning contractor, a copy of the service contract and service report shall be forwarded to the Landlord each quarter.

MINOR REPAIRS： To be responsible for all minor repairs and replacement of parts and other expendable items at its own expense up to Singapore Dollars Two Hundred Only (S$200.00) per item. In the event such expenditure exceeds S$200.00 per item, the Tenant shall bear the first S$200.00 and any excess thereof shall be borne by the Landlord. For repairs above S$200.00, Landlord’s approval must be obtained prior to such repair and the Landlord reserve the right to engage his contractor. However, repair costs will be borne in full by the Tenant if the repair is necessitated by the negligence of the Tenant.