Regrading comparison od Codetel's speed test and a remote speed test server (e.g. speakeasy or speedtest):
Remember one important thing: When you do a speed test on Codetel's website, you are connecting to a speed test server over Codetel's private network. You are actually not reaching the "public Internet". You ride the Codetel's backbone, which apparently has sufficient throughput.
Now when you do a speed test on the Internet, you go to the "public Internet" - the Codetel's backbone connects to the underlying Internet network (e.g. in Puerto Plata the Caribbean Crossing, etc.) and there what affects your speed is: a) the international bandwidth available at the moment (Codetel has certain bandwidth but has been a known case that the international bandwidth has been insufficient recently and especially during daily peak times things slow down considerably); and b) the public Internet network between the Codetel and the speed server you use, where a problem, slow down, congestion, time out etc. can occur at any point (hop) on the route; and c) the number of users that use the public speed test server.
Try making the speed test on codetel's website and on public speed test server at 3 to 4 am. The speeds should be virtually the same.