Am I playing with fire? (calling RPG subproc from CL)

Okay, so the CL Reference for my release (V5R4), says:
"A CL variable can be passed, in which case the called procedure must
declare the field to match the variable defined in the calling procedure.
For example, if a CL procedure defines a decimal variable named &CHKNUM as
(5 0), the called procedure must declare the field as packed with 5 digits
total, with no decimal positions.
If either a decimal constant or a program variable can be passed to the
called procedure, the parameter should be defined as (15 5), and any
calling procedure must adhere to that definition. If the type, number,
order, and length of the parameters do not match between the calling and
called procedures (other than the length exception noted previously for
character constants), unpredictable results will occur. "
I don't like unpredictable results :)
I have an RPG procedure with the following prototype.
D utrmDates_newDateTime...
D PR 2 0
D oldDate...
D D value
D oldTime...
D 6 0 value
D unitsToAdd...
D 9 0 value
D unitTypeIn...
D 7A value
D newDate...
D D
D newTime...
D 6 0
And my CL code:
DCL VAR(&startDate) TYPE(*CHAR) LEN(10)
DCL VAR(&startTime) TYPE(*DEC) LEN(6 0)
DCL VAR(&delayTime) TYPE(*DEC) LEN(9 0)
DCL VAR(&delayUnits) TYPE(*CHAR) LEN(7)
DCL VAR(&endDate) TYPE(*CHAR) LEN(10)
DCL VAR(&endTime) TYPE(*DEC) LEN(6 0)

chgvar &startDate '2007-04-13'
chgvar &startTime 130000
chgvar &delayTime 30
chgvar &delayUnits 'MINUTES'

callprc prc(UTRMDATES_newDateTime) +
parm((&startDate *byVal) +
(&startTime *byVal) +
(&delayTime *byVal) +
(&delayUnits *byVal) +
(&endDate *byRef) +
(&endTime *byRef) +
)

This *seems* to work fine - my concern is the fact that my CL varibles are
*CHAR while my RPG parameters are expecting dates. How safe is it to do
what I'm doing here?

TIA,
Adam

PS - Don't ask why I'm using "real" dates, but "fake" times ... I forget.
I think this procedure started life in an environment that required
numeric times.

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