It is clear from the Gemara that the second statement provides for a broader
range of exemption. What exactly is the point of argument between the two
versions? That is, what types of actions will be included in the exemption
according to the second version, but will not be included in the exemption
according to the first version?
(a) From RASHI (DH Ika d'Amri) it may be inferred that the first version is
only discussing Isurei Achilah which are Mutar b'Hana'ah -- items which are
forbidden to be eaten but from which it is permitted to derive benefit, such
as Neveilah. If something is Mutar b'Hana'ah, then only an act of "Achilah"
is prohibited. Eating it in an abnormal way is not called an "Achilah," even
though it might still be a Hana'ah, and therefore one is Patur for eating it
in such a way. However, if an object is also Asur b'Hana'ah one will not be
Patur for eating it in an abnormal way, because one has still derived
benefit from it.
The second version, though, holds that even if an item is Asur b'Hana'ah as
well, one is still Patur if he either eats the item in an abnormal manner or
has Hana'ah from it in an abnormal fashion.
(b) The MISHNAH LA'MELECH (Hilchos Yesodei ha'Torah, beginning of 5:8),
though, rejects this logic (without noting that it has a basis in Rashi's
words). Instead, he suggests another explanation. The only normal use of
Chelev, according to Rashi (DH Chelev), is to burn it as fuel or to rub it
into hides. Therefore, if one eats raw Chelev one is doubly modifying its
normal usage. First he is not burning or smearing it, but eating it, which
is not the normal form of Hana'ah that one gets from Chelev. Second, even
those few who deviate from the normal usage of Chelev and eat it do not eat
it raw; they cook it first. Hence, a person who *eats* *raw* Chelev is
deviating in two ways from the normal usage.
The first version of Rebbi Yochanan's statement requires one to make a
double change in order to be Patur. The *type* of Hana'ah that one gets must
be one that is not normally had from this item, and the *way in which* he
gets that type of Hana'ah must also be unusual.
The second version maintains that even if there is only one deviation from
the norm, such as using the forbidden item for a different *type* of usage
than normal, that suffices to exempt him, even though the *way in which* he
gets that type of Hana'ah does not deviate from the norm.
(c) The MISHNAH LA'MELECH suggests another approach based on the words of
the RAMBAM (Hilchos Ma'achalos Asuros 14:10) and on the MAGID MISHNAH (Ibid.
8:16). According to the first version of Rebbi Yochanan, one is Patur only
if he eats or has Hana'ah in a different way than normal. The second version
holds that if something is fit to be eaten, then *any Hana'ah at all* other
than eating is considered she'Lo k'Derech Hana'aso. One does not have to
change the normal manner in which he gets Hana'ah; the very fact that he is
getting Hana'ah in any way other than eating is already considered to be an
"unusual way" of deriving benefit.
(According to this understanding, when the Gemara says that if one is Patur
for smearing Chelev on a wound then certainly one is Patur for eating Chelev
Chai, even though one is getting Hana'ah by *eating* the item in the latter
case, the Gemara means that eating something in an *unusual* way, she'Lo
k'Darcho, has more reason to be Patur than deriving benefit from it in a
*usual* way.)