So - if they offer a 103.5% allocation rate (as you mention above) and charge €150 for their services then this is actually less than 100% for a lump sum investment of up to c. €4,300 and only above that do you start getting an actual topup on your investment? Not exactly clear from what you posted above or the link that you posted.You know about discount brokers and what they offer.
"In general our service will result in an enhancement in the region of 3 to 5% of the amount invested in the form of an increased allocation of units, an increased allocation rate, or a reduced annual management charge, which will be clearly stated on your policy document."