I'm wondering something else here. Is it possible, w/the link between woohooer and sp removed that this mod can affect the Massage Table? I had one of my sims give his wife who was pregnant a "Romantic Massage" and the next thing I knew the msg came up that she was feeling extra fertile and the twins chance jumped to 50%! Also, this mod seems to have removed the set number of sims in the household. I now have 9 sims in the household with #10 on the way and the "try for a baby" is still active. I have the house set at 8 sims.

I thought the fertility effects of a romantic massage were intentional and coming from EA/the base game. Are you certain it didn't do that prior to having Woohooer in play or when the mods were linked?

The StoryProgression household limit is not necessarily honored by other mods, it's what SP is allowed to do generally and is required for overstuffed households when they are not actively being played. So without the link there is no SP gating on that action for the active household. The Woohooer setting is NRaas > Woohooer > Try for Baby > Species: Human > Maximum Occupants for User Directed > (default is 0, which means no maximum).

Ok, I changed the setting. I think my elder sim became pregnant b/c I had the risky set pretty high. Other than that, no I'm not certain at all about the fertility rate. I never tried the massage table until after woohooer was installed. I'm in the process of testing that out now. It just came as a huge surprise for me. Fortunately, the game crashed and she went back to a single baby. The reason I've not tried some of these things is b/c I was playing apocalypse style and most of the time, it just wasn't allowed.

It comes from the massage table I looked inside my ccmerged in the BUFF XML
<BuffList>
<BuffName>MassageTable_HighFertilityStore</BuffName>
<BuffDescription>MassageTable_HighFertilityStoreDescription</BuffDescription>
<Category>Physical</Category>
<AxisEffected>Happy</AxisEffected>
<EffectValue>20</EffectValue>
<TimeoutLength>1440</TimeoutLength>
<SKU>Store</SKU>
<Stackable>False</Stackable>
<Hex>MassageTable_HighFertilityStore=0x9A7F5F1919DF001B</Hex>
<CustomClassName>Sims3.Store.Objects.MassageTable+HighFertilityStore, StoreObjectsMassageTable</CustomClassName>
<ThumbFilename>moodlet_MTfert</ThumbFilename>
<Version>0.1</Version>
</BuffList>

Ok, I tested it out w/o woohooer in and the first time he did it her twins chance jumped up to 50%, but on the 2nd and 3rd try, it went back to the default. Thanks Sitting Bear!