Lag when calling BLS Transaction from within another

Question

Using MII 12.0.
In MII class, they told us a "best practice" was to check the "Reload Transaction after Execution" box in the configuration of a Transaction call within a BLS.  The reasoning behind it was that should this not be checked, a previous result of that called BLS transaction would still be cached in memory and used instead of the newly assigned values from within your calling BLS.
Checking the "Reload transaction after Execution" box forces MII to reload that transaction when it is called.
In time analysis, what has been noticed is that there's a significant - up to 9 seconds - lag time when one BLS calls another BLS.  On a time-sensitive operation, that is an eternity.  That amount of overhead defeats any hope of using common code libraries.
Questions -
1.  Is this a true "best practice", or is it one that adds unnecessary overhead to a BLS? 
2.  If the calling BLS executes 1 time - but is subject to be executed multiple times over a certain interval - is checking the Reload box of the BLS it is calling unnecessary? 
3.  Even if you pass new data each time you call that BLS, is it still going to use/return whatever data it has cached until the cache expires?
4.  Is there another way to ensure that the called BLS uses the data you pass it (and returns the corresponding result set) without incurring the amount of overhead that we have noted? 
Thanks

Answer 1

The version we're on is 12.0.6 Build 13, and moving to  12.1 (something I am not directly involved in).  In this version, I'm not seeing the menu options you describe, so it's apparently in 12.1 or later. 
The issue we are having if the "Reload transaction after execution" box is not selected is indeed caching of values. 
For example -
BLS1 runs every 5 minutes
BLS2 is called from BLS1, and in this case, retrieves error log info from a table - a common module used by several BLS's.
BLS3 is also called from BLS1, and in this case, writes to an error log using information retrieved from BLS2 from within the execution of BLS1.  BLS2 & BLS3's calls are in 2 separate sequences, one after the other. 
If BLS2 & BLS3 DO NOT have the "Reload Transaction after execution" checked, each will run with whatever the cached data in memory is for them, even though inside BLS1 I am assigning values to the input of BLS1 to send to BLS2, and passing the returned data from BLS2 into BLS3.  Unless it's checked, BLS2 & BLS3 would continue to be called, however, it would be with whatever data has been cached for them. 
If that "Reload" switch is checked, it will reload each transaction & call it with whatever data is being passed.
This was mentioned in the MII class I was in also.  This is a generalization, but the way they described it was being similar to how you might save a web page to your local PC, and that unless that page is refreshed & changed, that from that point on, every time you brought up your saved web page, it would always display the same values in it.  They didn't go into great deal to explain the mechanics of it, but MII would only load it the first time it executed, and that unless you forced it (by checking the Reload switch), it would always execute using the same cached values no matter what you were passing.