From 1016 to 1030 the Normans were pure mercenaries, serving either Byzantines or Lombards, and then Sergius of Naples, by installing their leader Rainulf in the fortress of Aversa in 1030, gave them their first pied-à-terre and they began an organized conquest of the land.
Between 1016 and 1030 was about 14 years.
1030 - 1016 = 14, therefore the statement "Between 1016 and 1030 was about 14 years." is definitely correct. 
( z0 mean :ARG1 ( z1 between :op 1016 :op 1030 ) :ARG2 ( z2 about :op ( z3 temporal-quantity :quant 14 :unit ( z4 year ) ) ) )
(z0 / mean-01
    :ARG1 (z1 / between
              :op1 1016
              :op2 1030)
    :ARG2 (z2 / about
              :op1 (z3 / temporal-quantity
                       :quant 14
                       :unit (z4 / year))))
Between 1016 and 1030 was about 14 years .
z1 :op1 0
z1 :op2 1
z0 :ARG1 z1
z0 :ARG2 z2
z3 :quant 2
z2 :op1 z3
z3 :unit z4