Actually, i'm not a non-network savvy.
You've made some mistakes in your assesment of bit and byte:
250kb/sec is 250 kilo BITS/sec, not BYTES. You didn't use a capital B.
1Mb/sec = 125kB/sec, not 100kb/sec. Didn't use a capital B and you provided the wrong number.
Also, DSL speed is not as...