Dave,

The Pronto hex is very close between both commands.
The only difference I see is the gap (the final
hex word) between frames 0680 v. 0689 and that
minute difference will not matter.

To be hyper-technical the NECx2 protocol per the
Samsung data sheet calls for 108 mS total frame
lengths. To have MakeHex calculate that you
would use these statements in the irp file:

Device=7.7
Function=0..255

Protocol=NECx2
Frequency=38000
Time Base=564
One=1,-3
Zero=1,-1
Prefix=8,-8
Message Time=108m
Default S=D
Form=;*,D:8,S:8,F:8,~F:8,1

The difference being that I removed the suffix=
statement and replaced the "_ " at the end of
the form statement with a 1. I also added the
Message Time=108m and make hex will adjust that
final off time so that the frame length will be
exactly 108 mS. MakeHex calculates the Pronto
hex to be 06E9. Again, this is not the issue
here, since all of those gap numbers are close
enough to work. 0680, 0689, and 06E9 represent
43, 44, and 47 microseconds respectively. IR accuracy
is generally +/-10%

That value will vary slightly when you change
the device number. The Default S=D statement will
allow you to use Device=7.7 or Device=7 and get
the same results. Most other NEC family protocols
use Default S=255-D that is the binary complement
of device. By convention NEC1:24 means that the
subdevice is the binary complement or NEC1:24.231.
AFAIK, most if not all NECx variants have S=D,
but 7.7 seems easier to reduce confusion.

All these conventions were established largely
by John Fine who has also written a number decoding
programs for Pronto ccf and hex and RTI TT cml
files.

There is a readme file with MakeHex that covers
some of these points, but I learned it's features
through using it a lot and a similar program written
by Barry Gordon that shared their irp syntax initially
but both have drifted to some degree as John and
Barry added features.