This is common if you have a small subnet delegated from your ISP. It's called RFC 2317 delegation or something like that.
Many ISPs will have you create a PTR record, under your domain (i.e. oscar.com which you have control over), and put a CNAME in their reverse zone (i.e. 0.168.192.in-addr.arpa which the ISP has control over).
For example, for an IP address of 126.96.36.199, the reverse record would be 188.8.131.52.in-addr.arpa. A reverse lookup would look for that record from the owner of the IP address (in your case, myhosting.com or their parent ISP).
The ISP would normally have a record like
184.108.40.206.in-addr.arpa IN PTR net223ip15.myhosting.com
But in the cname delegation method, they have something like this:
220.127.116.11.in-addr.arpa IN CNAME 15.oscar.223.222.221.oscar.com
Then you create a record in your zone like this:
15.oscar.223.222.221.oscar.com IN PTR www.oscar.com
Then folks will look up 18.104.22.168 and follow the CNAME from 22.214.171.124.in-addr.arpa to 15.oscar.223.222.221.oscar.com to www.oscar.com.
I've never had this done for a single IP, but I've had several ISPs do something like this for routed subnets.
Check with myhosting.com to see if they have a preference or specification for the record. But I think this is the general story behind the delegation.