Can you at least tell us which regulations you believe state this?
from CAO 95.55:
1.1 This Order applies to a single-place or 2-place aeroplane that:
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(e) is mentioned in paragraph 1.2
1.2 For subparagraph 1.1 (e), an aeroplane must be 1 of the following:
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(e) an aeroplane, the major portion of which has been fabricated and assembled by a person who undertook the construction project solely for the person’s own education or recreation...
6 General conditions
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(f) in the case of an aeroplane to which this Order applies by virtue of subparagraph 1.2 (b), © or (f) — the aeroplane must not have been modified without the approval of CASA or of an authorised person for the purposes of regulation 35 of CAR 1988;
(g) in the case of an aeroplane to which this Order applies by virtue of subparagraph 1.2 (a), (e) or (g) — the aeroplane must:
(i) before its initial flight, have been inspected by a person authorised by CASA for that purpose; and
(ii) if any condition or limitation has been imposed under paragraph 6.3 — be operated subject to that condition or limitation.
If the limitation comes from 6(f), that does not apply to amateur built aircraft (subparagraph 1.2 (e) ) - only subparagraph 1.2 (b), © or (f).
I am looking for something that applies only to the builder but I don't see it. It seems like another case of someone reading the regulations to mean what they think they SHOULD say, rather than what they actually say...